At scotts printing company LLC there are two kinds of printing presses: Model A which can print 50 books per day and Model B which can print 30 books per day .The company own 9 total printing presses and this allows them to print 390 books per day How many of each type of press do they have?

there are 6 model A printing presses.

there are 3 model B printing presses.

Step-by-step explanation:

Let x represent the number of Model A printing presses.

Let y represent the number of Model B printing presses.

The company own 9 total printing presses. This means that

x + y = 9

Model A which can print 50 books per day and Model B which can print 30 books per day. The company own 9 total printing presses and this allows them to print 390 books per day. It means that

50x + 30y = 390 - - - - - - - - - - - -1

Substituting x = 9 - y into equation 1, it becomes

50(9 - y) + 30y = 390

450 - 50y + 30y = 390

- 50y + 30y = 390 - 450

- 20y = - 60

y = - 60/ - 20

y = 3

x = 9 - y = 9 - 3

x = 6