Bill has saved $825 from his last 8 paychecks. He saved either $75 or $150 a paycheck. For the 8 paychecks, how many times did Bill save $75 from his paycheck?

Declaration

Let x = number of times he saved 75 dollars.

Let y = number of times he saved 150 dollars

Equations

75*x + 150*y = 825 (1)

x + y = 8 (2)

Solve

Multiply 2 by 75

75x + 150y = 825

75x + 75y = 600 (3) Subtract (3) from (2)

75y = 225 Divide by 75

y = 225/75

y = 3

Therefore x = 8 - 3 = 5

Conclusion

Be very careful what you conclude from this

x = the number of 75 dollars saved. The total for 75 dollars * 5 = 375

y = the number of 150 dollars saved. The total for 150 dollars * 3 = 450 Add

Total 825