Answer:
Jon is 10 years old
Step-by-step explanation:
This is solved using linear equations. We use the information given to make equations.
Let's use K for Kylie, E for Ellie, and J for Jon:
K = E + 5
K = J x 3
Now, we rearrange these equations so that K is on the right side:
E = K - 5
J = K/3
Now, with only one variable, we make a new equation:
K + (K - 5) + (K/3) = 65
Simplify:
2K - 5 + K/3 = 65
Isolate k:
[tex]\frac{7k}{3}-15=65(3) = 195\\7k=196+15=210\\k = \frac{210}{7}=30[/tex]
Now we can plug K in to find Jon's age:
J = K/3
J = 30/3
J = 10
