Four staff members at a certain company worked on a project. The amounts of time that the four staff members worked on the project were in the ratio 2 to 3 to 5 to 6. If one of the four staff members worked on the project for 30 hours, which of the following CANNOT be the total number of hours that the four staff members worked on the project?
A. 80
B. 96
C. 160
D. 192
E. 240
2:3:5:6
其中一個30個小時
我計算出來結果total number of hours有可能為190,160,96,80以及其倍數
但是如果是這樣的話,好像每一個都是答案

請問各位大大如何解之
thank you!!!