Question 285998
Tom, eighteen years old, is three times as old as his brother.
Tom is 18, brother is 6
:
How old will Tom be when he is twice as old as his brother?
:
Let t = no. of years for Tom's age to be twice as his brother's age
:
t + 18 = 2(t + 6)
t + 18 = 2t + 12
18 - 12 = 2t - t 
t = 6 years
:
Tom will be 18+6 = 24 yrs
Bro will be 6+6 = 12 yrs