Answer:
see the explanation
Explanation:
Let
D -----> Danielle's age
C -----> Counselor's age
we know that
----> equation A
----> equation B
substitute
equation A in equation B
----> equation that can be used to find Danielle's age
Solve for D


Find the value of C
----> equation that can be used to find Counselor's age
substitute the value of D
therefore
Danielle's age is 7 and Counselor's age is 21