Question 1039572
Let 
x = number of years that pass by


Walter is currently 43 years old. His daughter Paulette is currently 7 years old.


Present Ages
walter = 43
paulette = 7


If we fast foward x years into the future, this means 
walter's age = 43+x
paulette's age = 7+x
simply add x to each value


We want to know when these future ages will be tied together through the following idea
(paulette's age) = (1/3)*(walter's age)


which is equivalent to saying

(walter's age) = (3)*(paulette's age)


So this means 


(walter's age) = (3)*(paulette's age)


(43+x) = (3)*(7+x)          ........ apply substitutions


43+x = 3*7+3*x


43+x = 21 + 3x


43+x-x = 21 + 3x-x


43 = 21 + 2x


43-21 = 21 + 2x-21


22 = 2x


2x = 22


2x/2 = 22/2


x = 11


So if 11 years pass by, then Walter will be 43+11 = 54 while Paulette will be 7+11 = 18. Notice how 18*3 = 54. Put another way, 18 is one-third of 54.



So the final answer is 11 years.