[求助]一題PS>"

baobaobears

one millisecond is 0.001 of a second. The costs for a single run of a computer program are $1.07 for operating system overhead, $0.023 per millisecond of computer time, and $4.35 for the mounting of a data tape. What is the total of these three costs for 1 run of a program that requires 1.5 seconds of computer time?

A) $7.15
B) $8.87
C) $28.96
D) $35.57
E) $39.92

anwer:E

請大大幫忙解題

看了好久 實在是不知怎麼算 謝謝囉^^

zhangxirui02

1.5 seconds is equal to 1.5*1000 millisecond, which is 1500 milliseconds. It costs 0.023 dollar per millisecond, that gives us 0.023*1500=34.5 dollars. You have to plus 1.07 and 4.35 for extra costs. This will give you 34.5+1.07+4.35=39.92 dollars.

baobaobears

恩恩 其他我都懂了 

只有一個地方

就是1.5 seconds為什麼會等於1.5*1000millsecond呢?

請大大解答^^"

linlin3151

因为题干第一句话说，one millisecond is 0.001 of a second. 换句话说，就是a second is 1000 millisecond，于是1.5 seconds equal to 1.5*1000 milliseconds.