+0  
 
0
476
3
avatar

A father is 9 times as old as his son. In three years, the father will be 6 times as old as his son.

How old is the son?

 Jan 22, 2021
 #1
avatar+73 
+6

I think the son is currently 6 years old. You can plug this answer in and solve the question backwards.

By the way I make videos, and I would really appreciate it you if you chekced my YouTube channel out. It is called Nyan Cat Gaming, but you can just search up Nyan Cat Gaming Valerie. TYSM!!!!

 Jan 22, 2021
 #2
avatar+505 
+1

Close, but not quite.

Let x be the age of the father and let y be the age of the son.

\(x=9y\\ x+3=6(y+3)\\ 9y+3=6y+18\\ 3y=15\\ x=5\)

So the son is actually 5 years old.

textot  Jan 22, 2021
 #3
avatar+267 
+1

use systems of equations

 

the two systems are: 

 

f=9s

f+3=6(s+3)

 

steps: 

1. expand 6(s+3) to get 6s+18

2. substitute f in terms of s (and we know that f=9s, so then the second equation becomes 9s+3=6s+18

3. now we know how to solve. add -6s to both sides, add -3 to both sides, and finally divide both sides by 3. 

 

We get: 

 

f=45, s=5

 

so the son is 5 years old and the father is 45 years old

 Jan 22, 2021

2 Online Users

avatar