GRE Numeric Entry Sample Questions

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1. Question :

Find the value of (n-r), when 7/2<(r+5)/2<=4 and P(n,r)=60

Correct Answer:

2

Explanation:

7/2<(r+5)/2<=4

7<r+5 <=8

7-5 <r<=8-5

2 <r<=3

r=3

P(n,r)=60

n!/(n-r)!=60

n!(n-3)!=60

n(n-1)(n-2)(n-3)!/(n-3)!=60

n(n-1)(n-2)=60

5*4*3=60

n=5

Hence, (n-r)=5-3

=2

2. Question :

Find the least possible value of x, (5x-2)/3-(7x-3)/5>=x/4

Correct Answer:

4

Explanation:

(5x-2)/3-(7x-3)/5>=x/4

(25x-10-21x+9)/15>=x/4

(4x-1)/15>=x/4

4(4x-1)>=15x

16x-4>=15x

x>=4

Hence, the least possible value of x is 4.

3. Question :

Find the value of k for which the equations have infinite solutions.

(k-3)x+3y=k and kx+ky=12

Correct Answer:

6

Explanation:

For infinite solutions, we have the condition

(k-3)/k=3/k=k/12

(k-3)/k=3/k and 3/k=k/12

k(k-3)=3k and 3*12=k*k

k^2-3k=3k and k^2=36

k^2=6k and k=-6,6

k=0, 6 and k=-6, 6

k=6

GRE Numeric Entry Sample Questions

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