Age problem algebra

Question

Alex is five times as old as Jim, but in twelve years he will only be three times as old. How old is each now.

Answer 1

I interpret the problem in following manner, the ratio Alex's current only age to Jim's decreases as Jim ages.

Let Jim's age = x

Let Alex's age = 5x

When Jim's age is

x + 12

Alex's current age is

3(x + 12)

So right now

3(x + 12) = 5x

Give it a try.

I have Jim at 18 and Alex at 90

x = 18

5x = 90

And

x + 12 = 18 + 12 = 30

3(x + 12) = 3(18 + 12) = 3( 30) = 90