Post: Did You Know these Facts about GRE Math?
Question: How many positive integers, less than 20, are either an even multiple of 2 or, a multiple of 9 or, the sum of a positive multiple of 2 and a positive multiple of 9?
Answer: There are 11 such integers:
- Multiples of 2 – 4, 8, 12, 16 (total 4)
- Multiples of 9 – 9, 18 (total 2)
- Sums of a positive multiple of 2 and a positive multiple of 9 – 11, 13, 15, 17, 19 (total 5)
Post: Quantitative Comparison Questions: Doubtful D!
Question:
X < (1/X)
Column A Column B
X X2
Answer:: (D)
The given inequality is X< (1/X).
This is possible only in two cases:
(1) If 0 < X < 1 OR
(2) X < -2
Now, you need to compare ‘X’ with ‘X2’
If you pick the value of ‘X’ from 1st range, let’s say ‘X’ = ½, then X > X2, thus the possible answer is option (A) and hence, options (B) and (C) can be eliminated.
But if you pick up the value of ‘X’ from the second range of values, lets say X = -3, then X < X2.
That means we are not able to reach to any unique conclusion using the information given, thus the answer is option (D)