Posted by Tory Smith on .
A university bookstore recently sold a wirebound graphpaper notebook for $2.64, and a collegeruled notebook for $3.61. At the start of spring semester, a combination of 50 of these notebooks were sold for a total of $168.86. How many of each type were sold?

Math 
helper,
x = number of graph notebooks
y = number of college ruled notebooks
2.64x = total value sold graph notebooks
3.61y = total value sold college notebooks
x + y = 50
2.64x + 3.61y = 168.86
Solve these 2 equations together by elimination or substitution method
I will use substitution method
x + y = 50
x = 50  y
2.64x + 3.61y = 168.86
2.64(50  y) + 3.61y = 168.86
132  2.64y + 3.61y = 168.86
132 + .97y = 168.86
.97y = 36.86
y = 38
substitute y = 38 in x + y = 50, to find x
x + 38 = 50
x = 12
12 graph notebooks were sold
38 college ruled notebooks were sold