A jar contains n nickels and d dimes. There are 22 coins in the jar, and the total value of the coins is $1.70. How many nickels and how many dimes are in the jar?

Answer 1

n + d = 22 <-- d = 22-n

5n + 10d = 170 <-- amount in pennies

5n + 10(22 - n) = 170

5n + 220 - 10n = 170

220 - 5n = 170

220 - 170 - 5n = 0

50 - 5n = 0

50 = 5n

n = 10

10 nickles and 12 dimes is worth $0.50 + 1.20 = $1.70

Answer 2

n+d=22

$0.05n+$0.10d=$1.7

Solve this system of equations.