SOLUTION: please help me solve my word problem {nine books are to be bought by a student. Some cost $6 each and the remainder cost $6.50 each.If the total amount spend was $56, how many of e

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: please help me solve my word problem {nine books are to be bought by a student. Some cost $6 each and the remainder cost $6.50 each.If the total amount spend was $56, how many of e      Log On


   

Question 1079717: please help me solve my word problem {nine books are to be bought by a student. Some cost $6 each and the remainder cost $6.50 each.If the total amount spend was $56, how many of each book are bought?}
Found 2 solutions by josgarithmetic, addingup:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
system%286x%2B6.5y=56%2Cx%2By=9%29

6x%2B6.5%289-x%29=56
6x-6.5x%2B58.5=56
-0.5x=56-58.5
0.5x=2.5
x=5
-
y=4
-

5 of the $6 books
4 of the $6.50 books

Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
Let the $6 books be x and the books at 6.50 y:
So we have:
x + y = 9 subtract y from both sides:
x = 9 - y
:
6x + 6.50y = 56 substitute for x
6(9 - y) + 6.50y = 56
54 - 6y + 6.50y = 56
0.50y = 2
y = 4
So the student got 4 books at 6.50 and 9 - 4 = 5 books at 6.
:
Check:
4 × 6.50 + 5 × 6 = 56
26 + 30 = 56 Correct.