Substitution math problem

Question

Whitney has a coin jar with a small collection of nickels and dimes. There are 69 coins in a the jar. They have a value of $5.90. How many Nickels and dimes are in the jar? I need help with work shown please!!

Answer 1

Use a system of equations.

n + d = 69

.05n + .10d = 5.90

Solve for n in the first equation. n = 69 - d

Now substitutes that into the second equation

.05(69 -d) + .10d = 5.90 Solving this will give you the number of dimes. The. Subtract that from 69 to get the number of nickels.

Answer 2

Let N be the number of nickels and D be the number of dimes. You're given that N+D=69 ("there are 69 coins in the jar"). You also know that the total value of the nickels is .05N and the total value of the dimes is .1D. Thus, you're also given that .05N+.1D=5.90.

Since N+D=69, we can write N=69-D. Then substituting in the last equation above, we get .05(69-D)+.1D=5.90. Solving for D will give the you the number of dimes. Then subtracting that from 69 will give you total number of nickels.