If Erin has 3 more dimes than nickels and they have a combined value of 120 cents, how many of each coin does she have?

Question

Help please!

Answer 1

Hello, thank you for taking the time to post your question!

The key on this type of question is to set up an expression that allows you to solve for the values of interest.

On this one we have

D = N + 3   because Erin has 3 more dimes than nickels

5N + 10D = 120  because they have a combined value of 120 cents

I would use substitution from there then in order to solve, so that means plugging in the first equation into the second

5N + 10(N + 3) = 120

5N + 10N + 30 = 120

15N = 90

N = 6, meaning that D = 6 + 3 = 9

So Erin has 6 nickels and 9 dimes

I hope that helps you get moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

 

Let x = be the number of nickels that Erin has

 

   x + 3 =  be the number of dimes that Erin has

 

0.05x  + 0.10 ( x + 3 ) = 1.20

 

Solve for x:  Multiply both sides of the equation by 100 to eliminate two  decimal places

 

   5x + 10x + 30 = 120

          

                15x  = 90

 

                   x = 6  ; Erin has 6 nickels

 

                 x + 3 = 9 ; Erin has 9 dimes

 

To check:  6 ( 0.05 )  + 9 ( 0.10 ) = 0.30 + 0.90 = 1.20