Billy purchased 100 shirts at a cost of 15 each and planned to resell them. The first week he sold some of them for25 each. The second week he sold the rest for 20 each. If his total profit was 600 , how many shirts did he sell the first week?
So first I find that he must have made 2100 dollars
+36915 Cost of shirts = 100 x 15 = 1500 Profit 600 total sales 2100
25 x = first week's sale 20 (100-x) = second week's sale added together = 2100
25x + 20(100-x) = 2100
5x +2000 = 2100
5x = 100
x = 20
+128408 Let the number of shirts he sold the first week = x and the number sold the second week = 100 - x
So we have
[Sales] - [Cost] = Profit
[25x + 20(100 - x)] - [15 * 100] = 600 simplify
25x + 2000 - 20x - 1500 = 600
5x + 500 = 600 subtract 500 from both sides
5x = 100 divide both sides by 5
x = 20 = the number of shirts sold the first week
