天山 07-03

[schung0529]

Pat, Kate, and Mark charged a total of 162 hours to a certain project. If Pat charged twice as much time to the project as Kate and 1/3 as much time as Mark, how many more hours did Mark charge to the project than Kate?

A. 18
B. 36
C. 72
D. 90
E. 108

答案: D

[waleaaa]

設 Pat, Kate, Mark 分別 charge P, K, M 小時─
由題目得知　P = 2K = 1/3*M　且 P + K + M = 162
可求出 P = 36　K = 18　M = 108
所以　M - K = 90