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.

step-by-step explanation:

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.