# GRE Numeric Entry SAMPLE QUESTIONS-3

## GRE Numeric Entry Sample Questions

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]

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.

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.

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]