SOLUTION: Mark is 60 years younger than Danielle. 3 years ago, Danielle's age was 4 times Mark's age. How old is Mark now?

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Question 661568: Mark is 60 years younger than Danielle. 3 years ago, Danielle's age was 4 times Mark's age. How old is Mark now?
Found 2 solutions by ReadingBoosters, MathTherapy:
Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
x = mark
y = danielle
x = y - 60
4(x - 3) = y - 3
Substitution
4(y-60)-3 = y - 3
Distribute the 4
4y - 240 - 3 = y - 3
Combine like terms
3y = 240
y = 80
x=80-60=20 years old for Mark

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
Mark is 60 years younger than Danielle. 3 years ago, Danielle's age was 4 times Mark's age. How old is Mark now?

Let Danielle's current age be D, and Mark's, M
Then: M = D - 60 ---- D = M + 60 ----- eq (i)

Also, D - 3 = 4(M - 3) ---- D - 3 = 4M - 12 ---- D - 4M = - 9 ---- eq (ii)

M + 60 - 4M = - 9 ------- Substituting M + 60 for D in eq (ii)
- 3M = - 69

M, or Mark's current age = %28-+69%29%2F-+3, or highlight_green%2823%29

You can do the check!!

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