What is the total weight of 5 textbooks and 5 notebooks?

Question

A middle school mathematics textbook weighs 2 1/2 pounds, and a spiral notebook weighs 4 ounces. What is the total weight of 5 textbooks and 5 notebooks?

A. 11 3/4 lb

B. 12 1/2 lb

C. 13 3/4 lb

D. 22 1/2 lb

Answer 1

1 text book weighs 2.5 pounds

5 text books weigh 12.5 pounds (5·2.5)

 

1 notebook weighs 4 oz

5 notebooks weigh 20 oz (5·4)

 

12.5 pounds + 20 oz

12 pounds 8 oz + 20 oz

12 pounds + 28 oz

12 pounds + 1 pound + 12 oz

13 pounds 12 oz

13 3/4 pounds

 

C.