Question

A can do a piece of work in 12days,b can do it in 16 days.A started to work alone . After how many days should b join him,so that the work is finished in 9 days?

Answer 1

Answer:

After 5 Days

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Step-by-step explanation:

A's 1 day work = 1/12

B's 1 day work = 1/16

Let A do alone work for x days

remaining days = 9-x

x/12 + (9-x)(1/12 + 1/16) = 1

x/12 + (9-x) (4 + 3)/48 = 1

4x + (9-x) (7) = 48

4x + 63 - 7x = 48

- 3x = - 15

x = 5

After 5 days B should join A