Question 924074: One day a store sold 21 sweatshirts. White ones cost $10.95 and yellow ones cost $12.50. In all, $248.55 worth of sweatshirts were sold. How many of each color were sold?
(-10.95)x+y=21 -> x=21-y
10.95x+12.50y=248.55
-10.95x-10.95y=229.95
1.55y=478.50
y=308.7
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! x = number of white ones
y = number of yellow ones
x + y = 21 (first equation)
10.95x + 12.50y = 248.55 (second equation)
from the first equation, solve for y to get y = 21 - x
in the second equation, replace y with 21 - x to get:
10.95x + 12.50(21-x) = 248.55
simplify to get:
10.95x + 262.5 - 12.50x = 248.55
combine like terms and subtract 262.5 from both sides of the equation to get:
-1.55x = -13.95
solve for x to get:
x = 9
that makes y = 12 because 12 + 90 = 21
your solution is that x = 9 and y = 12
that means that:
the store sold 9 white ones and 12 yellow ones.
9 * 10.95 + 12 * 12.50 = 248.55
your two equaitons had to be:
x + y = 21
that equation told you the number of shirts that were sold had to be equal to 21.
the other equation had to be:
10.95x + 12.50y = 248.55
that equation told you the total price for each type of shirt had to total up to 248.55.
total price for white shirt is 10.95 each times the number of white shirts.
total price for yellow shirts is 12.5 each times the number of yellow shirts.
by shirts, i mean sweatshirts.
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