Question

William has $12.80 in coins to be deposited in the bank. There are 3 times as many quarters as nickels and 20 more dimes than nickels. If n represents the number of nickels, what equation could be used to find the number of nickels to be deposited.

Answer 1

Let the number of nickels be = n

Let the number of dimes be = d

Let the number of quarter be = q

Total money William has = $12.80

As given, there are 3 times as many quarters as nickels

`q=3n`

And 20 more dimes than nickels

`d=20+n`

As total money is $12.80

`0.05n+0.10d+0.25q=12.80`

Putting the values of 'q' and 'd' to find 'n'

`0.05n+0.10(20+n)+0.25(3n)=12.80`

`0.05n+2+0.10n+0.75n=12.80`

`0.90n+2=12.80`

`0.90n=10.80`

`n=12`

Hence the number of nickels are = 12

If you want to also find dime and quarter, then

`q=3n=3*12=36`

`d=20+n=20+12=32`