Question

please solve it step by step

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Answer 1

Given that A can complete a work in 10 days.

Work done by A in 1-day = (1/10).

Given that B can complete the work in 12 days.

Work done by B in 1-day = (1/12).

Work done by A and B in 1-day = (1/10) + (1/12)

= 11/60.

Work done by A and B in 3 days = (11/60) * 3

= 11/20.

Remaining work = (1 - 11/20)

= 9/20.

Now,

9/20 of the work completed by B in (12 * 9/20) = 108/20 days.

Therefore, the total time taken = (108/20) + 3

= 168/20

= 42/5

= 8 (2/5) days.

Hope this helps!