Angel has a total of 97 dimes and nickels. if the total value of the coins is $8.35, how many dimes does he have

Dime=10 cents

nickles=5 cents

835=10d+5n

divide both sides by 5

167=2d+n

total number of coins is 97

97=d+n

we have

2d+n=167

d+n=97

multiply 2nd equation by - 1 and add them

2d+n=167

-d-n=97 +

1d+0n=70

d=70

sub back

d+n=97

70+n=97

minus 70 both sides

n=27

70 dimes

He would have $1.35 left