Question 348621
$5 bills =a


$10 = b


$20 = c


a=2b+4


b-6=c


Since the letters a,b and c represent the number of bills, we have to multiply by their value still since we only know how much money was in the wallet, not how many bills were in there.


5a+10b+20c=460


Now put it all in terms of b


5(2b+4)+10(b)+20(b-6)=460


10b+20+10b+20b-120=460


40b-100=460


40b=560


b=14 (there are 14 $10 bills)


but we want $5 bills and we know how to get there from the number of 10 dollar bills....


a=2b+4


a=2*14+4


a=32


There are 32 $5 bills in the wallet.