BTGModeratorVI wrote: ↑Mon Dec 28, 2020 8:29 am
If 1 < d < 2, is the tenths’ digit of the decimal representation of d equal to 9?
(1) d + 0.01 < 2
(2) d + 0.05 > 2
Answer:
B
Source: official guide
Given: 1 < d < 2
Target question: Is the tenths’ digit of the decimal representation of d equal to 9?
Statement 1: d + 0.01 < 2
Subtract 0.01 from both sides of the inequality to get: d < 1.99
So, it could be the case that d = 1.93, in which case the answer to the target question is
YES, the tenths digit is 9
Or it could be the case that d = 1.77, in which case the answer to the target question is
NO, the tenths digit is not 9
Since we can’t answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: d + 0.05 > 2
Subtract 0.05 from both sides of the inequality to get: d > 1.95
Since we already know that d < 2, we can combine these inequalities to get: 1.95 < d < 2
So, it MUST be the case that
the tenths digit is 9
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
