Math Help - money problem

Mr R coin bank consists of $10 bills and $5 bills only. if there 75 bills worth $ 450, how many $10 bills are there?

Originally Posted by rcs

Mr R coin bank consists of $10 bills and $5 bills only. if there 75 bills worth $ 450, how many $10 bills are there?

x = number of $10 bills

y = number of $5 bills

now, you set up two equations from the given information ...

please correct me if im wrong:

10x + 5y = 450
75( x+ y) = 450

Originally Posted by rcs

please correct me if im wrong:

10x + 5y = 450 this equation is ok ...

75( x+ y) = 450 this equation is incorrect ... x is the number of $10 bills , y is the number of $5 bills, the total number of bills is 75

... fix it.

Originally Posted by skeeter

... fix it.

10x + 5y = 450
x + y = 75

Originally Posted by rcs

10x + 5y = 450
x + y = 75

good ... solve the system.

Originally Posted by skeeter

good ... solve the system.

thank you skeeter great Mentor!