GMAT Practice Question: If 0<r<1<s<2, which of the following must be less than 1 ? I. r/s...
Question
If 0<r<1<s<2, which of the following must be less than 1 ? I. r/s II. rs III. s-r
- I only
- II only
- III only
- I and II
- I and III
Topics: inequalities, decimals
Solution
Step 1
Determine whether r/s is always less than 1 by comparing numerator and denominator
r < 1 s > 1 r/s < 1/s < 1
Step 2
Check whether rs must be less than 1 by testing with sample values
r = 3/4, s = 3/2 rs = 3/4 3/2 = 9/8 > 1
Step 3
Check whether s - r must be less than 1 by testing with sample values
s = 9/5, r = 1/2 s - r = 9/5 - 1/2 = 18/10 - 5/10 = 13/10 > 1
Answer
I only (A)
