Can you guys answer thouroly this math question plz?

Question

You have quarters dimes and nickels in a jar. There are twice as many quarters as nickels. Write an expression for the number of coins in the Jar. In terms of nickels and dimes. CAn you plz give me the answer i would really apreciate it

Answer 1

Let Q be the number of quarters
Let D be the number of dimes
Let N be the number of nickels

In the jar you would have Q + D + N coins.

But you are told that there are twice as many quarters as nickels. This means for however many nickels there are (N) you would double the number to get the number of quarters. As an expression you would write Q = 2N. Now just substitute this in for Q

Total coins = 2N + D + N

Simplify it is just in terms of nickels and dimes:
= 3N + D

P.S. Note they asked for the *number* of coins in the jar, not the value... but if they did you would use 25Q + 10D + 5N for the value in cents, then replace Q like before...

Answer 2

n = # nickels; d = # dimes; q = # quarters
total number of coins = N = n + d + q
twice as many quarters as nickels => 2n = q
N = n + d + q
N = n + d + 2n
N = 3n + d