I need help finding the value of j in this algebra problem

Question

So here’s the word problem:

Billy has 3/4 of the money Derek has, and Derek as 7/9 of the money Jason has. If they had a total of 680$, how much would each person have?

Here is the equation I found (J is the value of Jason’s money)

 

J+ 7/9J + (3/4 x 7/9)j = 680$

 

I am very stuvck on trying to find the value of J. An explanation would be helpful too!! Thanks you all very much!

Answer 1

Let x, y, z  denote the amount Billy, Derek and Jasob have. Then

x+y+z=680

x=(3/4)y  

y=(7/9)z

If you solve this system of equations, you have to obtain:

x=168, y=224, z=288.

 

You can solve by substitution, for example. By using the second and the second equations from the first one you get

(3/4)y+y+(9/7)y= 680.

y=224.

Then you find x and z.