Question 44217
He has $5.50 in nickels, dims, and quarters. He has twice as many quarters as nickels, and two fewer than four times the number of dimes as nickels. How many dimes does he have?

Let number of dimes be x
Then 4x-2 is number of nickels
And number of quarters is 8x-4
Value of dimes is 10x cents
Value of nickels is 5(4x-2)=20x-10 cents
Value of quarters is 25(8x-4)=200x-100 cents

EQUATION: 
value + value + value = 550 cents
10x + 20x-10+200x-100=550
230x-110=550
230x=660
x=?
This does not work out to be a whole number.
Either your statement of the problem is wrong or 
my reading of your statement is wrong.
Cheers,
Stan H.