Answer:
Lisa would be 7.
Explanation:
Substitute both Lisa and Kathy's ages for X values.
x + x - 16 = 30
Then add up the x's.
2x - 16 = 30
Add 16 to both sides.
2x = 14
Divide by 2 on both sides, and solve.
x = 7
Check your work by adding.
7 + 16 = 23
23 + 7 = 30