Carl can wash all the windows of his house in 6 hours. His wife Maggie can wash all the windows in 5 hours. How many hours will it take for both of them working together to wash all the windows?	Select.
A) 2	B) 2 1/4	C) 11 8/2	D) 4 1/2	E) 5
Work hrs=AB/(A+B)= 30/11 =11 8/2   Answer is 11 8/2
<result>C</result>
Carl can wash all the windows of his house in 6 hours. His wife Maggie can wash all the windows in 5 hours. How many hours will it take for both of them working together to wash all the windows?