Question

Dad is 4 times as old as his son Jim. In 10 years, Dad's age will be 20 years more than twice Jim's age. How old is Jim?

Answer 1

let d=dad, let j=jim
d=4j
2j+20=d
sub.
2j+20=4j
20=2j
j=10. Jim is 1o years old.
I think this is the answer, but i might be wrong with setting up the second equation..

Answer 2

i meant 10 not 1o sorry lol

Answer 3

Let son' s age today is x, therefore father's age today will be 4x
In 10 years father is 10 years older, therefore his age will be 4x+10 and Jim will be 10 years older as well. Hence Jim's age will be x+10,
From the question Dad will be 20 years more than twice Jim's age.
With that we get an equation
2(x+10) +20=4x+10
2x+20+20=4x+10
2x=30
X=15, 4x=60,
Those are the ages of Jim and his Father.