Question 46013
Sure...think of it this way...
If you have three quarters, how much money have you?  Well, 75 cents.
If you have ten quarters, how much money have you?  Well, 250 cents.
If you have q quarters, how much money have you?  Well, 25q cents.
In every case you multiply the number of quarters times 25 to get its total value.
The same is true for 5 cents per nickel...so....
The value of q quarters and q - 5 nickels is $3.05 becomes
25q + 5(q-5) = 305
Notice how it's 305 cents...we could also write this as
.25q + ,05(q-5) = 3.05 if we are talking dollars...
The equations are equivalent...