x - age of Esther and
y - age of Janet
Then, let's express the given conditions in math form.
For the first condition, Esther (x) is three times as old as Janet (y).
For the second condition, the sum of their ages is 20. So we have,
Then, substitute value of y to x=3y.
So, Esther is 15 years old and her sister Janet is 5 years old.
Knowing their age, let's solve their age difference.
Hence, the difference between their ages is 10 years.
let x be the age of janet, then ester age will be 3x
According to question
therefore,janet age is 5 years old while his brother is 3x5=15 years old.
so,as per the question difference between their ages is
15-5=10 years old