John has $5.00 in nickels and dimes. if he has twice as many dimes as nickels, how many of each coin does he have?

Here's what we know that we can put into an equation.
⇒The number of nickels mutliplied by .05 and the number of dimes multiplied by .1 equal 5.00.
⇒2n=d; that means that the number of nickels times 2 equals the number of dimes.
Let's solve:
We can use substitution with out two equations.
0.05n+0.10d= 5.00
2n=d
We can put the second equation in as the value of n in the first equation.
0.05n+0.10(2n)=5.00
Now solve till d has a value.
0.05n+0.2n=5.00
0.25n=5.00
5.00÷0.25=20=n
There are 20 nickels. If there are 20 nickels, there has to be 40 dimes since he has twice as many dimes as nickels. Let's check this with the other equation.
0.05(20)+0.1(40)
1+4=5
So, there are 20 nickels and 40 dimes.
Tell me if this helps!!