system of equations

Question

At Eugene's Printing Company LLC there are two kinds of printing presses: Model Awhichcanprint40 books per day and Model B which can print 70 books per day. The company owns 13total printing presses and this allows them to print 820 books per day. How many of each type of pressdothey have? A) 9 of Model A and 4 of Model B B) 11 of Model A and 2 of Model B C) 3 of Model A and 10 of Model B D) 10 of Model A and 3 of Model B

Answer 1

40A + 70B = 820

11A, 2B no

440+140 =580 not 820

3A, 10B YES

120 + 700 = 820 Yes

The Answer is C

9A, 4B No

99 + 280 = 379 not 820

10A, 3B No

110 + 210 = 320 not 820