✔ 最佳答案
Let cost = c
original sales quantity = q.
Selling price = c(1 + 25%) = 1.25c
Profit = 1.25cq - cq = 0.25cq.
New selling price = 1.25c(90%) = 1.125c
New quantity = Q,
so Profit = 1.125cQ - cQ = 0.125cQ.
Since profit increase by 25%, that is
(0.125cQ - 0.25cq)/0.25cq x 100% = 25%
(Q/8 - q/4)/(q/4) = 1/4
(Q - 2q)/8 = q/16
2(Q - 2q) = q
2Q - 4q = q
2Q = 5q
Q/q = 5/2 = 2.5 times.