Carcass wrote:
On the line segment AD shown below, AB = 1/2*CD and BD = 3/2*AC. If BC = 24, then AD =
(A) 24
(B) 48
(C) 72
(D) 96
(E) 120
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITIONGRE - Math Book GIVEN: BC = 24. Add this to the diagram.
Also, let
x = the length of CD
GIVEN: AB = (1/2)(CD)Since CD has length
x, we know that
0.5x = the length of AB
GIVEN: BD = (3/2)(AC)BD has length
24 +
xAC has length
24 +
0.5xSo, we can write:
24 +
x = (3/2)(
24 +
0.5x)
Expand right side to get: 24 + x = 36 + 0.75x
Subtract 0.75x from both sides to get: 24 + 0.25x = 36
Subtract 24 from both sides to get: 0.25x = 12
Solve:
x = 48If
x = 48, then
0.5x = 24Add this information to the diagram:
Length of AD =
24 +
24 +
48 = 96
Answer: D
Cheers,
Brent