2013 AMC 12B Problem 2

Question

Mr. Green measures his rectangular garden by walking two of the sides and finds that it is

15

steps by

20

steps. Each of Mr. Green’s steps is

2

feet long. Mr. Green expects a half a pound of potatoes per square foot from his garden. How many pounds of potatoes does Mr. Green expect from his garden?

600

800

1000

1200

1400

Answer: A

Concepts:unit conversion area rate

Difficulty rating: 1020

Small hint:

Convert steps to feet first: each step is

2

feet

Big hint:

Multiply the area in square feet by

\dfrac12

pound per square foot

Solution:

The garden is

2\cdot 15 = 30

feet by

2\cdot 20 = 40

feet, an area of

1200

square feet. At half a pound per square foot, Mr. Green expects

\tfrac12\cdot 1200 = 600

pounds. Thus, the correct answer is A.