Problema Solution
a university bookstore recently sold a wirebound graph-paper notebook for $2.50,and a college-ruled notebook for $2.30. At the start of spring semester, a combination of 50 of these notebooks were sole for a total of $118.60. How many of each type were sold?
Answer provided by our tutors
Let x = no. of graph notebooks; Let y = no. of college ruled notebooks
The number of items equation:
x + y = 50
So
x = (50 - y);
The second equation:
2.50x + 2.30y = 118.60
Substitute (50-y) for x, solve for y:
2.50(50-y) + 2.30y = 118.60
125 - 2.5y + 2.3y = 118.60
-2.5y + 2.3y = 118.6 - 125
-0.2y = -6.4
y = -6.4/-.2
y = 32 ruled note books
x = 50 - y
x = 50 -32
x = 18 graph note books