A can do 40% of a work in 12 days, whereas B can do 60% of the same work in 15 days. Both work together for 10 days. C completes the remaining work alone in 4 days. A, B and C together will complete 28% of the same work in:

2 days. A takes 30 days for full work B takes 25 days for full work LCM is 150.. so assume total work is 150 units A does 5units/ day B does 6u/ day 10 days together ==> 110 units. pending is 40 units which C completes in 4 days. C therefore does 10u/days/ 28% of 150 is 42 units.. total units by ABC in a day is 6+5+10= 21.. so days is 42/21 =2 days

2 days

2 days