Question

7) At Elisa's Printing Company LLC there are two kinds of printing presses: Model A which can print 70 books per day and Model B which can print 55 books per day. The company owns 14 total printing presses and this allows them to print 905 books per day. How many of each type of press do they have?

Answer 1

Simultaneous equations:

Makes the 2 equations, solving for A and B.
Let A = Model A and B = Model B

A + B = 14
70A + 55B = 905

70A + 70B = 980
70A = 980 - 70B - rearrange and substitute

980 -70B + 55B = 905
980 -15B = 905

-15B =-75
15B=75
B=5

There are 5 Model B's. So that means there must be 9 Model A's.