Step-by-step explanation:
Kim is 5 years older than Scott.
Kim's mum is 3 times Kim's age.
Scott's dad is 3 times Scott's age.
Let age of Scott = y years
Then Kim's age = (y+5) years
Kim's mum age = years
Scott's Dad age = years
Difference between Kim's mum age and Scott's Dad age = Kim's mum age - Scott's Dad age = (3y+15) - (3y) = 15
