Answer:
6 13/20 hours
Step-by-step explanation:
Addition of fractions requires they be expressed using a common denominator. Here, that will be 5·4 = 20, and the two fractions can be written as ...
2/5 = 8/20
1/4 = 5/20
Then the sum of the mixed numbers is ...
(4 2/5) +(2 1/4) = (4 +2) +(2/5 +1/4) = 6 +(8/20 +5/20)
= 6 13/20
It took Kareem 6 13/20 hours to clean the two rooms.
