Question

15 men finish a work in 210 days. But at the end of 100 days 15 additional men are employed then in how many days will work be completed

Answer 1

15 * 210 = 3150 total work

100*15 =1500 work done

Remaining = 3150-1500= 1650

And this remaining work is now done by 30 men's

Days = 1650/30 = 55 days

Hope I got it right