melguy wrote:If a,b and c are positive integers. What is the ratio of a
![:b:](//cdn.jsdelivr.net/gh/twitter/twemoji@latest/assets/svg/1f171.svg)
c?
1) b = 4 and ac = 21.
2) a/c = 3/7 and c/b = 7/4
Target question:
What is the ratio of a
c?
Statement 1: b = 4 and ac = 21
There are several sets of values that meet this condition. Here are two:
Case a: a = 3, b = 4 and c = 7, in which case
a
c = 3:4:7
Case b: a = 1, b = 4 and c = 21, in which case
a
c = 1:4:21
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: a/c = 3/7 and c/b = 7/4
a/c = 3/7 means that a:c = 3:
7
c/b = 7/4 means that c:b =
7:4
Since both ratios have c =
7 in common, we can combine the ratios to get a:c:b = 3:
7:4
Rearrange to get
a
c = 3:4:7
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer =
B
Cheers,
Brent