Hello friends welcome to TalentSprint

ever wondered what successful students

do that you don't ? what is the secret

behind their success in this highly

competive exams ? what is that one thing

which can help you crack these competitive

exams ? well the most certain answer for

this question is the approach that you

have for solving various questions in

your aptitude exams .I am sure most of

you feel that even I can answer this

question but what is the reason that I

am left behind well the difference

between a winner and the others is that

others know how to answer the question

but winners know how to answer the

question in a smart way so in this video

today I am going to show you a few

methods of answering questions or in

smart ways let us look at what are the

four ways of solving questions from

aptitude and I shall explain this to you

with the help of a few examples the

first question here it says the

principal amount is 20,000 time period

is 2 years and the rate of interest is

14% per annum

so what is the compound interest well

the first method of solving any question

in aptitude is the traditional method

the conventional method will be use the

step by step procedure to arrive at the

final answer but we end up wasting a lot

of time in most of the cases like in

this question if you go by the formula

of compound interest which says CI

equals to P into 1 plus R by 100 whole

to the power of t minus P or if you take

P common we have this formula for CI

right P of 1 plus R by 100 whole power t

minus 1 now all we need to do here is

substitute the values 20,000 rate of

interest is 14 and time period is 2 here

so substitute the values simplify do the

calculation and you will get the final

answer but I am sure most of you

understand that we will take at least

two minutes to solve all those equations

and arrive at the final answer so what

is the second method of answering this

question here well the second method

which is different from the traditional

method is to use your basic concepts

your basic fundamentals of answering

questions without

using the conventional formula like in

this case if you are strong in your

basics of percentages you would

understand that compound interest can be

calculated using the concept of

effective percentage which says that

effective percentage can always be

calculated as A plus B plus AB by 100

where A and B are two percentages so

compound interest is also an effective

percentage case and hence we can say

that the compound interest here in terms

of percentage will be equal to A plus B

plus AB by 100 where A is the rate of

interest in first year and B is the rate

of interest for the second year now

generally the questions that we get in

the exam have got the same rate of

interest for both the years so in our

case A is 40 and B also is 40 so let's

just substitute and find out what is the

compound interest in terms of percentage

so A plus B plus A into B by hundred

what do we get 14 + 14 + 14 *

14 / 100 now 14 squared is 196 . 196 upon 100

is 1.96 so 14 + 14 =28. 28 + 1.96

this will come out to be 29

.96%. so what we

understand from this approach is that

the compound interest in this case will

be twenty nine point nine six percent or

approximately 30 percentage thirty

percent of what the principal amount

right again if you are strong in your

concept here you would know that the

interest is always calculated on the

principal amount so we can say that the

component s in this case is 30

percentage of twenty thousand which is

six thousand rupees so that's how using

the second method where we follow the

basic fundamentals and basic concept we

can arrive at answer much faster without

following the traditional or the

convention method so the answer for this

question would be six thousand and I'm

sure you will be able to do this in less

than 30 seconds in your competitive exam so

you might wonder that why did we take

thirty percentage as the answer because

the actual calculation says it should be

29.96%. well

the reason here is that in competitive

exams most of the times the options are

given in such a way that we can do an

approximate calculation and arrive at

the

correct answer since the options are

generally not too close to each other

here we can assume that 29.96 is

approximately 30 percentage right and 30

percentage of principal amount here is

6000 option which is closest to 6000 can

be marked as the correct answer and

moreover we should also understand that

the answer has to be slightly lesser

than 6000 so if at all we find two

options that are close to 6000 but one

is less than 6000 and the other being

more than 6000 we can easily eliminate

the wrong answer here because we know

that answer is actual answer is 29.96

percentage which should be less than

6000 right so the idea here is to use

the concept of effective percentage and

do an approximate calculation to mark

the answer in less than 30 seconds

without following the Lengthy and

time-consuming conventional method so

this is the second method of answering

the questions from aptitude where we use

our basic knowledge and the concepts

that we have discussed in answering the

questions without using the formula or

the conventional method let us now look

at the third method of answering

questions from aptitude and this is

known as the substitution method well

there are many types of questions where

we can follow the method of substitution

right this is like a reverse engineering

all we need to do is put the option

answers back in the question and see

which option satisfies the given

question here right so we simply

substitute the answer options in the

question one after the other and the one

that satisfies the given question can be

taken as a correct answer

let's understand this with the help of

an example now here I have a question on

ages which says the ages of A and B are

in the ratio of 7 : 4 after 5 years

the ratio of their ages become 11 :

7 what is the age of A so here simply

two ratios have been given the first

ratio is 7 :4 for the second ratio

which is after 5 years becomes 11 :

7 and we have to find out what is the

age of the person A here and the given

answer options are 12 years 14 years 15

years and 28 years now most of the

students answer even this question using

the traditional method and end up

spending about 45 to 60 seconds to get

the right answer

but if you are smart and if you use the

substitution method you can mark the

answer for this question in less than 10

seconds so what do we do here try to

substitute the answer options back in

the question when the one point that you

need to observe here is A: B is in

the ratio of 7 : 4 their original

ages are in the ratio of 7: 4

let's look at it we can clearly

understand that is A's age has to be a

multiple of 7 the age of the person A

has to be a multiple of 7 if you look at

the answer options option A can we

substitute this here

no because 12 clearly is not a multiple

of 7 so this gets ruled out let us now

look at second option here second option

says A's age is 14 years so substitute A

equals to 14 now what happens if A is 14

years it is a multiple of 7 right so the

first condition is satisfied but the

second conditions is after five years is

A's age has to be a multiple of 11 now if you

assume that 14 is the correct

answer 14 + 5 that is A's age after 5

years would be 19 but he is 19 a

multiple of 11

no so even this option gets eliminated

so basically we are substituting 14 back

in the question to see if it satisfies

both the conditions or not let us now

substitute the third option that is 15

years is A's age is 15 years if you substitute

15 year what happens we will say 15 by B

equal to 7 by 4 but since most of the

times the questions here should have the

answer will be a integer value we know

that 15 is not a multiple of 7 so even

this does not seem to be the right

answer so we can you know who rule this

answer out and look at the last option

of 28 years since already three of the

answer options have been eliminated we

can say that option 4 is the correct

answer

by the way if option 4 here that is 28

years or option D 28 years let's say is

somewhere in the first position then

what do we do substitute back right 28

years let's substitute A equals to 28 does

that satisfy the first condition .Yes A's age

has to be multiple of 7 . 28 is a multiple

of 7 now what happens the second part of

the question says after 5 years

the ratio becomes 11 : 7 now A's age

is 28 years after 5 years it would

become 33. 28

+ 5 is 33 is that a multiple

of 11 yes it is so we see that the

fourth option here or option D here

satisfy both the conditions of the given

question

hence this has to be the correct answer

so this is how in substitution method we

just try to substitute back the answers

in the given question and see which

option satisfies the question are the

conditions given in the question and let

us now see the fourth method of

answering questions from aptitude and

this method is known as elimination

method now what exactly happens here we

don't find out the correct answer

instead we find out what are the wrong

answers that is to eliminate the wrong

answer options we know that we have got

four answered options here out of which

one is correct and three are wrong so we

either find out the correct answer or

find out which three are wrong and there

are many questions where finding out the

three wrong answers would be much much

easier than finding out the one correct

answer there and these type of questions

can be answered using elimination method

let's understand this method with the

help of a simple example here now this

question from simplification says

question mark squared plus seventy nine

squared equals to 172 squared minus 88

squared minus 8203 and

we have to find out what comes in place

of question mark again if you go by the

traditional method we'll end up wasting

a lot of time right

following the conventional method will

take at least one and half to two minutes for us

to get the required answer if you do not

know how to find out the squares of a

number mentally

however we know that will not be

following traditional method here

instead we'll use elimination method

that is to eliminate the wrong answers

from the given answer options now how do

we do that in this question follow the

unit digit method what we do here is

find out what can be the unit digit of

the given question

and based on that we can eliminate the

wrong answers let us do that we know

that when a number ends in nine its

square would end in one any number that

ends in nine the square of that number

would end in one because 9 squared is 81

right 19 squared is 361 29 squared is

841 so always when a number ends in 9

the square ends in one

so we know that 79 square is a number

that ends in one it will be a four digit

five digit number that ends in one four

digit number that ends in one now let us

follow a similar procedure for the

remaining numbers as well

172 square when a number ends in 2

square ends in 4 likewise 88 square when

a number ends in 8 its square also ends

in 4 right so these are you know four

digit numbers that end in 4 and this

last number here is 8 2 0 3 which is a

straightforward number that ends in 3

here all right now let us try to do the

simplification we have to find out what

comes in place of question mark here

right now the idea here is to balance

the unit spaces on both the sides if you

look at the right hand side there is a

number that ends in 4 minus another

number ending in 4 now one number ends

in 4 the other number also ends in 4

when we take the difference we know that

it will end in zero for example 124

minus 74 would end in 0 4 minus 4 gives

us 0 so 4 minus 4 here is 0 now we have

a number that ends in 0 minus a number

that ends in 3 now one number ends in 0

and the other number ends in 3 the

result would end in don't say minus 3 if

you know the concept here you will see

that it ends in 7 because what do we do

we borrow 1 from the next digit make it

10 and 10 minus 3 will give us 7

so clearly the right-hand side of this

equation ends in 7 if the right-hand

side ends in 7 it is obvious that if the

left-hand side should also add up to 7

now already we have a number that ends

in 1 so what should come in placed off

the agreed place of question mark square

so that it is 7

see 1 plus 6 will be equal to 7 so

clearly question mark square should be

ending in 6 now we know that question

mark square ends in 6 right some number

squared ends in 6 so what can be the huge

space of that number it can be either 4

or 6 right when a number ends in 6 if

you take square root on both the sides

what do we get

question mark will be equal to square

root of some number ends in 6 ending in

6 and when a number ends in 6 its square

root ends in either 4 or 6 so now we are pretty clear

that the question mark should be a

number that ends in either four or six

let's check that from the answer options

option a number ends in six so maybe the

right answer look at option B ends in

nine can this be the correct answer

no eliminated option C ends in three

eliminated option B also ends in three

eliminated so we see that option B C and

D cannot be the correct answers because

the correct answer has to either end in

four or six and now that we are left

with only one choice we can say that it

has to be in the correct answer so the

answer for this question is 86 following

the elimination method so this is how

based on the question we can apply any

of these four methods that is the

traditional method or methods of using

your basic concepts and fundamentals or

the elimination method or the

substitution method to find out the

answer now you should follow this

approach and understand which method

suits for the given type of question and

the only way to do that is practice more

and more on various types of aptitude

questions so I hope all of you have

followed the four different ways of

solving questions from aptitude now all

you need to do is practice more and more

and make sure that you apply the best

method out of these four methods to

solve the given question and arrive at

the given answer without any difficulty

see you in the next video thank you

you