A contractor finds a bill for $1,210 for 520 ceiling tiles. She knows that there were two types of tiles used; one selling at $2.00 a tile and the other at $3.00 a tile. How many of each type were used?
A) 170 tiles of the first type were used,
350 tiles of the second were used.
B) 340 tiles of the first type were used,
130 tiles of the second were used.
C) 350 tiles of the first type were used,
170 tiles of the second were used.
D) 350 tiles of the first type were used,
120 tiles of the second were used.
E) 350 tiles of the first type were used,
140 tiles of the second were used.

Question

Quizplus · Accepted Answer

Let x be the number of tiles sold at $2.00 and y be the number of tiles sold at $3.00. We know that x + y = 520 (the total number of tiles used) and 2x + 3y = 1210 (the total cost of the tiles). We can then solve for x and y using these two equations. First, we can solve for x in the first equation as x = 520 - y. We can then substitute this expression for x into the second equation, giving us 2(520-y) + 3y = 1210. Simplifying this equation, we get 1040 - 2y + 3y = 1210, or y = 170. We can then use this value for y to find x as x = 520 - y = 350. Therefore, 350 tiles were sold at $2.00 and 170 tiles were sold at $3.00, so choice C is correct.

A Contractor Finds a Bill for $1,210 for 520 Ceiling