Problema Solution
Dorothy is 5 years older than her brother william. If the product of their ages is 204, how old is Dorothy?
Answer provided by our tutors
Let
x = Dorothy's age
y = William's age
x = y + 5 follows y = x - 5
We also know that:
xy = 204
Plug y = x - 5 into the last equation:
x(x - 5) = 204
........
click here to see the equation solved for x
........
x = 17 years
We need to ignore the negative solution -12 because the age can not be negative.
Dorothy is 17 years old.