working independently , tina can do a certain job in 12 hours . working independently , ann can do the same job in 9 hours . if tina works independently at the job for 8 hours and then ann works independently , how many hours will it take ann to complete the remainder of the jobs ?
work done by tina in 1 hr = 1 / 12 work done by tina in 8 hr = 1 / 12 * 8 which is 2 / 3 now , the remaining work is 1 / 3 which is completed by ann in 1 / 3 * 9 which is 3 hr answer : e
divide(9, divide(12, subtract(12, 8)))