A, B and C can separately do a work in 12, 15 and 20 days respectively. They started to work together but C left after 2 days. The remaining work will be finished in how many days?
4 days
Let the remaining work be done in x no. of days. Then,
x+212 + x + 215 + 220 = 1
⇒ (x + 2) × 960 = 1 − 110
⇒ x = 4