Question 948607
N=number of nickels; D=number of dimes=N+10
$0.05N+$0.10D=$2.20 Substitute for D.
$0.05N+$0.10(N+10)=$2.20
$0.05N+$0.10N+$1.00=$2.20 Subtract $1.00 from each side
$0.15N=$1.20 Divide each side by $0.15
N=8 ANSWER There are 8 nickels.
CHECK:
D=N+10=8+10=18 There are 18 dimes
$0.05N+$0.10D=$2.20
$0.05(8)+$0.10(18)=$2.20
$0.40+$1.80=$2.20
$2.20=$2.20