Question

A can do a piece of work in 12 days and b can do it in 20 days. a worked for 9days and leaves the work

Answer 1

let work be 120 ( lcm of 12 and 20 )

A needs 12 days
so A doing 10 work per day


B needs 20 days
so A doing 6 work per day

first A does work for 9 days

therefore 9×10 =90 work accomplish

now A leaves , B joins , 30 work remains

B doing 6 work per day so

for 30 work B takes 30/6 = 5 days

so remaining work B completes in 5 days

or total 9 + 5 =14 days requires