If Liam arranges chairs in 9 rows of the same length, he has 3 chairs left over. If he arranges the chairs in 7 rows of that same length, he has 19 left over. How many chairs does Liam have?

Let x represent the number of chairs in a row and y total number of chairs that Liam has.

We write system:

9*x + 3 = y

7*x + 19 = y

9*x + 3 = 7*x + 19

2x = 16

x = 8 That means that row's length is equivalent of 8 placed chairs.

Liam has:

7*8+19 = 56 + 19 = 75 chairs.