Question

And b together can finish a piece of work in 12 days. If a alone can finish the same work in 20 days in how many days b alone can complete it

Answer 1

A work in 1 day = 1/20...... (1)
they both work in 1 day = 1/a + 1/b = 1/12
from 1 we have....
1/20 + 1/b = 1/12
=>1/b = 2/3
=>1 /b = 1/30
=> b = 30 days ....
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