GRE Numeric Entry Sample Questions

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1. Question :

Find the probability of the occurrence of exactly one of A and B when P(AUB)=0.59 and the probability of the
occurrence of both A and B is 0.01. [AUB=A union B]

Correct Answer: 0.58

Explanation:

Probability of occurrence of exactly one of A and B=P(AUB) – probability of occurrence of both A and B

=0.59 – 0.01

=0.58

2. Question :

Find the value of (3/y-1/x) if 3(2x+y)=7xy and 3(x+3y)=11xy.

Correct Answer: 1

Explanation:

Let 1/x=u and 1/y=v

The two equations can be rewritten as

6x+3y=7xy and 3x+9y=11xy

6/y+3/x=7 and 3/y+9/x=11

6v+3u=7 and 3v+9u=11

The equations now are

3u+6v=7 …(1)

9u+3v=11 …(2)

Multiplying (1) by 3 and subtracting from (2), we get

9u+3v-9u-18v=11-21

-15v=-10

v=2/3

u=1/3(7-6*2/3)

=1/3(21-12)/3

=9/9=1

Hence, x=1/u=1 and y=1/v=3/2

3/y-1/x=3/(3/2)-1/1

=2-1=1

3. Question :

The simple interest on a sum of money is 1/6 of the principal. The number of months of investment is equal to
twice the rate percent. Find the time in months of the investment.

Correct Answer: 20

Explanation:

Let the principal be Rs.x.

The simple interest will be Rs.x/6

Let the rate of interest be y%.

The time in months will be 2y

Simple interest=P*R*T/100, where P, R and T are the principal, rate and interest.

x/6=(x*y*2y/12)/100

y^2=100

y=10

Hence, the time in months is 2*10=20 months

[y^2=y*y]

GRE Numeric Entry Sample Questions

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