Problem Solving

A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

14
13
11
9
7

pl explain...
source-gmatclub.

advita wrote:A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

14
13
11
9
7

pl explain...
source-gmatclub.

find # days (must be integer value)

(1/24 + 1/30 + 1/48 + 1/60)D=1 => D=240/27 => D=~8.8 or 9 (integer value)

IOM D 9

advita wrote:A furniture manufacturer has two machines, but only one can be used at a time. Machine A is utilized during the first shift and Machine B during the second shift, while both work half of the third shift. If Machine A can do the job in 12 days working two shifts and Machine B can do the job in 15 days working two shifts, how many days will it take to do the job with the current work schedule?

14
13
11
9
7

pl explain...
source-gmatclub.

One days Job for machine A and B = 3/2*(1/24+1/30) = 9/80
Hence no. of days = 80/9 = 9.