1 nickle = 5 cents
1 dime = 10 cents
$4.45 = 445 cents
let
n = the number of nickles, n>=0
d = the number of dimes, d>=0
a jar containing only nickels and dimes contain a total of 60 coins:
n + d = 60
the value of all the coins in the jar is $4.45:
5n + 10d = 445
by solving the system of equations:
n + d = 60
5n + 10d = 445
we find:
n = 31 nickels
d = 29 dimes