BTGModeratorVI wrote: ↑Sun Jul 19, 2020 1:49 pm
What was the percent increase in the value of a certain antique from January 1, 1981, to December 31, 1981?
(1) The value of the antique on January 1, 1981, was $3,000.
(2) The value of the antique on December 31, 1981, was double the value of the antique on January 1,1981.
Answer:
B
Source: GMAT paper tests
Target question: What was the percent increase in the value of a certain antique from January 1, 1981, to December 31, 1981?
Percent increase = 100(new - old)/old
So, we can answer the
target question if we have the OLD value and the NEW value.
Statement 1: The value of the antique on January 1, 1981, was $3,000.
Okay, so we have the OLD value, but we don't know the NEW value.
So, we don't have enough info to answer the
target question
Statement 1 is NOT SUFFICIENT
Statement 2: The value of the antique on December 31, 1981, was double the value of the antique on January 1, 1981.
Although we aren't given specific numbers for the OLD value and NEW value, we still have enough information. Here's why:
Let
x = the value of December 31, 1981
This means
2x = the value on January 1, 1981
When we apply the above formula, we get: percent increase =
100(
2x -
x)/
x = 100x/x = 100
So, the answer to the
target question is 100 percent
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
