Eleana and her grandfather both had birthdays last week.

The sum of their ages is 100 years.

Her grandfather’s age is 4 times Eleana’s age.

How old is Eleana and her grandfather?

Eleana is 20 years old.

Her grandfather is 80 years old.

Step-by-step explanation:

Suppose Eleana's age is "x". That means her grandfathers age is 4x.

x+4x= 100

5x=100  Divide both sides by 5

x=20   That means Eleana is 20 years old.

           Her grandfather would be 4 times her age so his age would be 40  years old.