SOLUTION: Joel has twice as many CDs as Mariella has. Subtracting 7 from the number of CD's Joel has and dividing by 3 equals the number of CDs blake has. If Blake has 25 CDs how many CDs do

Algebra ->  Equations -> SOLUTION: Joel has twice as many CDs as Mariella has. Subtracting 7 from the number of CD's Joel has and dividing by 3 equals the number of CDs blake has. If Blake has 25 CDs how many CDs do      Log On


   

Question 869180: Joel has twice as many CDs as Mariella has. Subtracting 7 from the number of CD's Joel has and dividing by 3 equals the number of CDs blake has. If Blake has 25 CDs how many CDs does Mariella have?
Answer by XilliX(3) About Me  (Show Source):
You can put this solution on YOUR website!
We can write each of the statements as an equation
1. Joel j has twice the number of CDs as Mariella m, hence
  j=2m

2. Joel's number of CD's - 7 divided by 3 equals the number of CDs Blake b has:
  %28j-7%29%2F3=b

3. Blake has 25 CDs
b=25


Substituting (3) into (2) gives:
  %28j-7%29%2F3=25
  j-7=3x25
  j-7=75
  j=75%2B7
  j=82

So Joel has got 82 CD's

Based on equation (1) we can calculate the number of CD's Mariella has:
  82=2m
  m=82%2F2
  m=41


Mariella has 41 CDs
Joel has 82 CDs
Blake has 25 CDs