Question

5 years ago, my grandfather was five times as old as I was. Three years from now, my grandfather will be three times as old as I will be. how old am I now?

Answer 1

Answer:

13 years

Step-by-step explanation:

5 years ago, let the grandchild's age to be x so the grandfather's age will be 5x.

3 years from now, the grandchild's age will be x+8 (x+3+5) and the grandfather's age will be 5x+8 (5x+3+8).

So we can establish an equation:

$5x+8=3(x+8)$

$5x+8=3x+24$

$5x-3x=24-8$

$2x=16$

$x=8$

Therefore, the present age of the grandchild is x+5 = 8+5 = 13 years and the present age of the grandfather is 5x+5 = 5(8)+5 = 45.

Answer 2

Answer:

13 years old

Explanation:

Let g and m represent grandfather's age now and my age now. The relation 5 years ago was ...

... g -5 = 5(m -5)

The relation in 3 years will be ...

... g +3 = 3(m +3)

Subtracting the first equation from the second, we get ...

... 8 = -2m +34

... 2m = 26 . . . . . add 2m-8

... m = 13

My age now is 13.