Question 864539
LET X BE THE NUMBER OF $20 BILLS
LET X+7 BE THE NUMBER OF $10 BILLS.
20X+10(X+7)=610
20X+10X+70=310
30X=310-70
30X=240
X=240/30
X=8 $20 BILLS.
8+7=15 $ 10 BILLS.
PROOFS:
20*8+15*10=310
160+150=310
310=310