GMAT-Introduction
1) If r and s are both positive integers, and k is the remainder when 5(10r) + s is divided by
3, what is the value of k?
(1) r = 10
(2) s = 1
Explanation:
Statement I is insufficient:
s = 1, remainder is 0 and s = 2 remainder is 1
Statement II is sufficient:
5(10r) + 1 will always be divisible by 3 as the sum of digits should be divisible by 3.
So Answer is B.
2) Is x >y?
(1) Both x and y are greater than 1
(2) x2 > y2
Explanation:
Statement I is insufficient:
x = 3 and y =2. x greater than y.
x = 2 and y =3. x not greater than y.
So not sufficient.
Statement II is insufficient:
x = 3 and y =2 . then x greater than y.
x = -3 and y =2 . then x not greater than y.
So not sufficient.
Together it is sufficient.
x is positive and greater than 1.
x = 3 and y =2 only this satisfies both the statements.
So it is sufficient. x is greater than y.
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So answer is C.
3) What is the value of |x|?
(1) x2 = 16
(2) x2 - 8x + 16 = 0
Explanation:
Statement I is sufficient:
x2 = 16
x = +/-4
|x| = 4.
So sufficient.
Statement II is sufficient:
x2 - 8x + 16 = 0
x = 4.
So sufficient.
So Answer is D.
4) What is the value of x?
(1) x is a two digit number which is divisible by 25
(2) The unit digit of x is not equal to 0.
Explanation:
Statement I is insufficient:
‘x’ can be 25,50 or 75.
So not sufficient.
Statement II is insufficient:
Clearly not sufficient. Many values for x.
So not sufficient.
So Together I and II is still not sufficient.
2
Because x can be 25 and 75.So not sufficient.
So the Answer is D.
The devil lies in the details!
5).The ratio of men to children on a tour is 8:3. How many men are there?
I.
Ratio of children to women is 5:13
II.
There are fewer than 50 women on the tour.
Explanation:
M/C = 8 :3 . Number of men?
Statement I is insufficient:
C/W = 5 / 13. This nothing talk about number of men. This talks about only ratios.
So not sufficient.
Statement II is insufficient:
This statement tells number of women less than 50. So nothing about men
So not sufficient.
But together it is sufficient.
Because from statement I we get
M : C: W = 40 : 15 : 39.
And statement II says number of women is less than 50.
So only choice is number of men to children to women is 40:15:39.
So the number of men is 40.
So the Answer is C.
Plug-In:
6) If n is an integer greater than 6, which of the following must be divisible by 3?
A.
B.
C.
D.
n (n+1) (n-4)
n (n+2) (n-1)
n (n+3) (n-5)
n (n+4) (n-2)
3
E. n (n+5) (n-6)
Explanation:
Clearly for a must be Question PLUG-IN.
PLUG IN -- n = 7(n>6).
A.
B.
C.
D.
E.
n (n+1) (n-4) ----- 7. 8 . 3
n (n+2) (n-1) ----- 7. 9 . 6
n (n+3) (n-5) ----- 7. 10. 2
n (n+4) (n-2) ----- 7. 11. 5
n (n+5) (n-6) ----- 7. 12. 1
divisible by 3
divisible by 3
not divisible by 3. So strike this option.
not divisible by 3. So strike this option.
divisible by 3
PLUG IN -- n = 8(n>6).
A.
B.
C.
D.
E.
n (n+1) (n-4) ----- 8 . 9. 4
n (n+2) (n-1) ----- 8. 10. 7
n (n+3) (n-5)
n (n+4) (n-2)
n (n+5) (n-6) ----- 8. 13. 2
divisible by 3
not divisible by 3. So strike this option.
Already we striked it off.
Already we striked it off.
not divisible by 3. So strike this option.
So the answer is A.
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