prep里的一道题目

laihuiyuan

At a certain supplier, a machine of type A costs $20,000 and a machine of type B cost $50,000.Each machine can be purchased by making a 20 percent down payment and repaying the remainder of the cost and the finance changes over a period of time.If the finance changes are equal to 40 percent of the remainder of the cost,how much less would 2 machines of type A cost than 1 machine of type B under this arrangement?

A10,000

B11,200

C12,000

D12,800

E13,200

答案为E

taohuaxian

A：先付20000×20%=4000.过段时间后付剩余的钱加上finance change（是什么意思，偶也不知，不过不影响做题啦！~）：20000×80%+40%×（20000×80%）=22400.所以两台的A价格是52800.
同理，一台B的价格是50000×20%+50000×80%×1.4=66000.
66000-52800=13200.