Question

The person A can do a piece of work in 12 days while the person B can do it in 15 days . if they both work together in how many days will they do it together?
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Answer 1

Answer:

(1/15+1/12)x=1

((1*4/15*4)+(1*5/12*5))x=1

(4/60+5/60)x=1

(9/60)x=1

(60/9)(9/60)x=1(60/9)

x=6 2/3 or 6.6666666 days to do the job together.