Question

kevin and randy muise have a jar containing 84 coins all of which are either quarters or nickels. the total value of the coins in the jar is 12.40. how much of each type of coin do they have

Answer 1

Let the number of nickels be n, then the number of quarters is 84-n.
The value of 1 qtr is 25c and the value of 1 nickel is 5c.
The total value is 5n+25(84-n)=1240 (in cents).
5n+2100-25n=1240, 20n=860, n=860/20=43.
So there are 43 nickels (worth $2.15) and 41 quarters (worth $10.25).