Quote:
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?
A. 14
B. 13
C. 11
D. 9
E. 7
A. 14
B. 13
C. 11
D. 9
E. 7
Let us look for LCM f 15 and 12. Say 60 is total work.
A completes in 12 days 2 shifts which means it works 2.5 hrs per shift. (60/12 = 5 hrs two shifts)
Similarly B completes in 15 days or works 2 hrs per shift.
Now, per day work as per shift plan 2.5 (A) + 2 (B) + (2.5 + 2)/2 (A and B combined) = 6.75 hrs per day
Total time = 60/6.75 which comes around 9 days.