2018 AMC 8 Problems/Problem 9

Revision as of 09:37, 13 June 2019 by Irrationalkid (talk | contribs) (Solution 2)

Problem 9

Tyler is tiling the floor of his 12 foot by 16 foot living room. He plans to place one-foot by one-foot square tiles to form a border along the edges of the room and to fill in the rest of the floor with two-foot by two-foot square tiles. How many tiles will he use?


$\textbf{(A) }48\qquad\textbf{(B) }87\qquad\textbf{(C) }91\qquad\textbf{(D) }96\qquad \textbf{(E) }120$

Solution

He will place $(12\cdot2)+(14\cdot2)=52$ tiles around the border. For the inner part of the room, we have $10\cdot14=140$ square feet. Each tile takes up $4$ square feet, so he will use $\frac{140}{4}=35$ tiles for the inner part of the room. Thus, the answer is $52+35=\boxed{\textbf{(B) }87}$

Solution 2

The area around the border: (12 * 2) + (14 * 2) = 52. The area of tiles around the border: 1 * 1 = 1. Therefore, 52/1 = 52 is the number of tiles around the border.

The inner part will have (12 - 2)(16 - 2) = 140. The area of those tiles are 2 * 2 = 4. 140/4 = 35 is the amount of tiles for the inner part. So, 52 + 35 = 87

See Also

2018 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 8
Followed by
Problem 10
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AJHSME/AMC 8 Problems and Solutions

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