Question

Moe uses a mower to cut his rectangular $90$ -foot by $150$ -foot lawn. The swath he cuts is $28$ inches wide, but he overlaps each cut by $4$ inches to make sure that no grass is missed. He walks at the rate of $5000$ feet per hour while pushing the mower. Which of the following is closest to the number of hours it will take Moe to mow his lawn?

$0.75$

$0.8$

$1.35$

$1.5$

$3$

Answer: C

Concepts:unit conversion rate area

Difficulty rating: 1100

Solution:

The lawn has area $90 \cdot 150 = 13{,}500$ square feet.

Each foot Moe walks mows an effective strip $2$ feet wide, so he mows $2 \cdot 5000 = 10{,}000$ square feet per hour. The time needed is $\dfrac{13{,}500}{10{,}000}=1.35$ hours.

Thus, the correct answer is C.

2003 AMC 10B Problem 5

Answer: C

Difficulty rating: 1100

Solution:

Problem 5 in Other Years