Question

A can do a work in 10days which is done by B in 15 days and by C in 20 days.They work together for 4days and B leaves.In how many days C and A together will finish the remaining work​

Answer 1

do LCM with minus

and 1 piece of work

Answer 2

A = 10days

B = 15days

C = 20days

total unit of work is 120 unit

for 1day,

A = 12 unit in 1 day

B = 8 unit in 1 day

C = 6 unit in 1day

so,

A+B+C = 12 + 8 + 6 = 26 unit in 1 day

so,

4 day = 26* 4 = 104 unit

remaining work = 120 - 104 = 16 unit

so

C + A = 6 + 12 = 1day

18 unit = 1day

1 unit = 1/18 days

16 unit = 16/18 = 8/9 days