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 and her grandfather is 80 years old.

Step-by-step explanation:

So first off, we want to make variables to represent Eleana and her grandfather.

Let x represent Eleana's age.

Since her grandfather is four times older than Eleana,

The expression should be 4x+x=100

Step One

Add the x's together and you get 5x=100.

Step Two

Divide both numbers by 5 to solve for x.

x=20