Answer:
Felicia is 7 years old
Step-by-step 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! :)