Quantitative Aptitude – Arithmetic – Time and Work


Slot – 1 – Quantitative Aptitude – Arithmetic – Time and Work – Three men and eight machines can finish a job

Q. Three men and eight machines can finish a job in half the time taken by three machines and eight men to finish the same job. If two machines can finish the job in 13 days, then how many men can finish the job in 13 days?

Answer: 13

Solution: Let a man can finish the job alone in M days.
Given two machines can finish the job in 13 days so one machine can finish the job in 13*2 = 26 days
As given that Three men and eight machines can finish a job in half the time taken by three machines and eight men to finish the same job
So 3/M + 8/26 = 2(8/M + 3/26)
3/M + 4/13 = 16/M + 3/26
16/M – 3/M = 4/13 – 3/13
13/M = 1/13
M = 169
So the number of men required to finish the job in 13 days = 169/13 = 13

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