I need help with an algebra problem? I'm so stuck!

I've run through this problem and tried to do it myself but didn't get reasonable results...please explain in an easy manner! Thank you!

Mary Jo has $3.90 worth of nickels, dimes, and quarters. The number of nickels is 3 more than the number of dimes. The number of quarters is 7 more than the number of dimes. How many of each coin is in her collection?
(then theres a table that looks like this)

------------Nickels Dimes Quarters
Number:_____________________________
Value:_______________________________


thanks in advance!!

While guessing works for some of these problems, it is still important to learn how to use algebra to solve these problems (since guessing does not work well on some problems, and your teacher may want to see how you set up and solve the equations).

Let d = number of dimes

Since the number of nickels is 3 more than the number of dimes,
d + 3 = number of nickels

Since the number of quarters is 7 more than the number of dimes,
d + 7 = number of quarters

The total value of the dimes is 10d cents.
The total value of the nickels is 5(d + 3) cents.
The total value of the quarters is 25(d + 7) cents.

Since the total value of all the coins is 390 cents, we have the equation

10d + 5(d + 3) + 25(d + 7) = 390
10d + 5d + 15 + 25d + 175 = 390
40d + 190 = 390
40d = 200
d = 5

number of dimes = d = 5
number of nickels = d + 3 = 5 + 3 = 8
number of quarters = d + 7 = 5 + 7 = 12

There are 8 nickels, 5 dimes, and 12 quarters.

Lord bless you today!

Q = number of quarters
N = number of nickels
D = number of dimes

.25(D+7) + .05(D+3) + .1D = 3.90
.25D + 1.75 + .05D + .15 + .1D
.4D = 3.90 - 1.90
.4D = 2.00
D = .50

The total of the number of dimes must = $0.50 (that's 5 dimes).
Since the number of quarters is the number of dimes + 7 = 12 quarters.
Since the number of nickels is the number of dimes + 3 = 8 nickels.

D = 5 ($0.50)
Q = 12 ($3.00)
N = 8 ($0.40)

300 would be 12 quarters

then you got 5 dimes which makes you have 350

and you have 8 nickels which makes it 390

Basically... You just have to figure out how many quarters you have. Once you know that you have 3 more nickels than dimes and 7 more quarters than dimes. Don't worry it works out.

390 = 10D+5(D+3)+25(D+7)
390 = 10D+5D+15+25D+175
200 = 40D
Dimes = 5
Nickels = 8
Quarters = 12

There should be 9 quarters 5 dimes and 14 nickels HOPE I HELPED:D

why would someone do your math for free? lol What do we get for it?