Mathematics

Third task

Kamil reckoned that the numbers of years of his parents are in the ratio 6 : 5 this year. After 12 years, this ratio will change to 8 : 7. Kamil’s mum is younger than his dad. By how many years?

Solution:

We describe the difference in the number of years by the sign “x”.

Dad is 6x years this year, Mum is 5x years, therefore she is younger by x years.

We make up the equation expressing the ratio of the parents’ ages after 12 years.

This year: Dad 36 years old, Mum 30 years old

36 : 30 = 6 : 5

After 12 years: Dad 48 years old, Mum 42 years old

48 : 42 = 8 : 7

Kamil’s mum is 6 years younger than his dad.