How many nickels and dimes do I have

Question

I open up my piggy bank and find that I have loads of dimes and nickels. The total number of dimes and nickels is 876 and when I calculate how much they are worth I find that I have $65.05 how many nickels and dimes do I have

Answer 1

Here's that popular system of equations again. This time involving coins. As with any one of these, you'll need two equations: one for numbers of coins, another for the value. Best to work in pennies to avoid decimals.

(1) D + N = 876

(2) 10D + 5N = 6505

Can use elimination or substitution method. This is via substitution.

N = 876 - D

10D + 5(876 - D) = 6505 Use distribution rule to eliminate parentheses.

10D + 4380 - 5D = 6505

5D = 2125

D = 425 N = 876 - 425 N = 451

Check: $0.10 x 425 = $42.50; $0.05 x 451 = $22.55 $42.50 + $22.55 = $65.05