SOLUTION: Your dad is 34 years older than your brother. Five years ago, your dad was three times as old as your brother. How old are they now? What I know already: x-y = 34

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Your dad is 34 years older than your brother. Five years ago, your dad was three times as old as your brother. How old are they now? What I know already: x-y = 34      Log On


   

Question 200189: Your dad is 34 years older than your brother. Five years ago, your dad was three times as old as your brother. How old are they now?
What I know already:
x-y = 34
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Let
x=your dad's age (right now)
y=your brother's age (right now)


so this means that
x-5=your dad's age 5 years ago
y-5=your brother's age 5 years ago

Since "Your dad is 34 years older than your brother", this means that x=y%2B34 which can be rewritten as x-y=34. So our first equation is x-y=34


Also, because "Five years ago, your dad was three times as old as your brother", we know that x-5=3%28y-5%29

x-5=3%28y-5%29 Start with the given equation.


x-5=3y-15 Distribute


x=3y-15%2B5 Add 5 to both sides.


x-3y=-15%2B5 Subtract 3y from both sides.


x-3y=-10 Combine like terms.


So our second equation is x-3y=-10


So you just need to solve the system

system%28x-y=34%2Cx-3y=-10%29

to find x and y. I'll let you do that.


If you have any questions, email me at jim_thompson5910@hotmail.com.
Check out my website if you are interested in tutoring.