BTGModeratorVI wrote: ↑Wed Oct 07, 2020 7:23 am
If cx - bx^3 = 0 where b and c are non-zero numbers, what is the value of b - c ?
(1) cx = c
(2) bx = b
Answer:
D
Source: 800 score
Given: cx - bx³ = 0
Target question: What is the value of b - c ?
Statement 1: cx = c
Since we know that c ≠ 0, we can safely divide both sides of the equation by c to get: x = 1
Now plug x = 1 into a given equation,
cx - bx³ = 0
We get:
c(1) - b(1³) = 0
Simplify to get: c - b = 0, which means c = b, which means
b - c = 0
Since we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: bx = b
Since we know that b ≠ 0, we can safely divide both sides of the equation by b to get: x = 1
Now plug x = 1 into a given equation to get:
c(1) - b(1³) = 0
Simplify to get: c - b = 0, which means c = b, which means
b - c = 0
Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
