a and b can do a work in 10 days and 15 days respectively . a starts the work and b joins him after 3 days . in how many days can they complete the remaining work ?
"work done by a in 3 days = 3 / 10 remaining work = 7 / 10 work done by both a and b in one day = 1 / 10 + 1 / 15 = 5 / 30 = 1 / 6 remaining work = 7 / 10 * 6 / 1 = 21 / 5 = 4 1 / 5 days . answer : d"
subtract(add(inverse(add(inverse(15), inverse(10))), 10), const_3)