SOLUTION: Anna has 12 bills in her wallet, some $5 and some $10. The total value of the bills is $100. How many of each bill does Anna have?

Algebra ->  Trigonometry-basics -> SOLUTION: Anna has 12 bills in her wallet, some $5 and some $10. The total value of the bills is $100. How many of each bill does Anna have?      Log On


   

Question 104407: Anna has 12 bills in her wallet, some $5 and some $10. The total value of the bills is $100. How many of each bill does Anna have?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
12 bills total
$5 and $10 bills possible
$100 total
Let F be the number of $5 bills and T be the number of $10 bills.
1.F%2BT=12Bill total equation.
2.5%2AF%2B10%2AT=100Value equation.
Use equation 1 to solve for T and substitute into equation 2.
1.F%2BT=12
T=12-F
2.5%2AF%2B10%2AT=100
5%2AF%2B10%2A%2812-F%29=100Value equation.
5F%2B120-10F=100Distributive property.
-5F%2B120=100Simplify.
-5F%2B120-120=100-120Additive inverse of 120.
-5F=-20Multiplicative inverse of (-5).
F=4Number of $5 bills.
T=12-F=8Number of $10 bills.
Number of $5 bills is 4.
Number of $10 bills is 8.