az780 wrote:

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 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

I solved this qs bt it took me some time, please advise shortcut to this problem.

D. 192.

total = 2+3+5+6 = 16

if 30 hours is workedby a worker whose ration is 2, then total = 30/2 x 16 = 180

if 30 hours is workedby a worker whose ration is 3, then total = 30/3 x 16 = 160

if 30 hours is workedby a worker whose ration is 5, then total = 30/5 x 16 = 96

if 30 hours is workedby a worker whose ration is 6, then total = 30/6 x 16 = 80

so 192 is no where.

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