8)
If w is 10% less than x, and y is 30% less than z, they wy is what percent less than xz?
(A) 10%
(B) 20%
(C) 37%
(D) 40%
(E) 100%
Answer: Choice C is correct. We solve using simple equations:
w is 10% less than x w = x - 0.10x, or w = 0.9x
y is 30% less than z y = z - 0.30z, or y = 0.7z
wy = (0.9x)(0.7z) = 0.63xz , or xz - 0.37xz