Danny is older than felicia. the difference between their ages is 21. the sum of their ages is 35. how old is felicia?

Felicia is 7 years old

Explanation:

The variable, d, can represent Danny's age.

The variable, f, can represent Felicia's age.

Basically, using the information provided, you can make two equations.

1.) d - f = 21

2.) d + f = 35

This is a system of equations. To solve for this, I'm going to subtract the 2 equations:

    d - f = 21

-   d + f = 35

    -2f = -14

       f = 7

If Felicia is 7, and they're total ages added is 35, subtract 7 form 35

35 - 7 = 28

So, Danny would be 28.

To double check your answers;

28 + 7 = 35

28 - 7 = 21

So Felicia is 7 years old. I hope this helps! :)