Vincen wrote: ↑Sat Mar 06, 2021 11:01 pm
Janson's salary and Karen's salary were each \(p\) percent greater in \(1998\) than in \(1995.\) What is the value of \(p?\)
(1) In \(1995\) Karen's salary was \(\$2,000\) greater than Jason's.
(2) In \(1998\) Karen's salary was \(\$2,440\) greater than Jason's.
Answer:
C
Source: GMAT Prep
Target question: What is the value of p?
Given: Jason's salary and Karen's salary were each p percent greater in 1998 than in 1995.
IMPORTANT: If my 1998 salary is p percent greater than my 1995 salary, then: 1998 salary = (1 + p/100)(1995 salary)
For example, if my 1998 salary is 7 percent greater than my 1995 salary, then: 1998 salary = (1 + 7/100)(1995 salary) = 1.07(1995 salary)
Let
K = Karen's salary in 1995
Let
J = Jason's salary in 1995
So,
(1 + p/100)K = Karen's salary in 1998
And
(1 + p/100)J = Jason's salary in 1998
Statement 1: In 1995 Karen's salary was $2,000 greater than Jason's
So, we get
K - J = 2000
So there's no information about p, so
we can't determine the value of p
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: In 1998 Karen's salary was $2,440 greater than Jason's
We get:
(1 + p/100)K -
(1 + p/100)J = 2400
NOTICE that we can rewrite this as:
(1 + p/100)(K - J) = 2400
Since we cannot solve this equation for p, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined
From statement 1, we concluded that
K - J = 2000
From statement 2, we concluded that
(1 + p/100)(K - J) = 2400
Now take the second equation and replace (K - J) with 2000 to get: (1 + p/100)(
2000) = 2400
At this point, we need only recognize that
we COULD solve this equation for p, but we're not going to, since this would waste valuable time on the time-sensitive GMAT.
Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C
Cheers,
Brent
