A change machine at an arcade gives change for $1 bills and $5 bills. On Monday, 200 bills were inserted into the machine. The total value of the bills was $300 How many $1 bills were inserted into the machine on Monday?

Let n = the number of $1 bills

So......200 - h = the number of $5 bills...so we have this equation

1*n + (200-n) *5 = 300

1n + 1000 - 5n = 300

Can you take it from here ???