Final answer:
Kathy worked 17 hours at Job A and 13 hours at Job B to make a total of $193.90.
Step-by-step explanation:
To solve this problem, let's assume Kathy worked x hours at Job A and (30-x) hours at Job B. We can set up an equation to represent the total earnings:
5.90x + 7.20(30-x) = 193.90
Solving this equation, we find that:
5.90x + 216 - 7.20x = 193.90
-1.30x = -22.10
x = 17
Therefore, Kathy worked 17 hours at Job A and 13 hours at Job B to make a total of $193.90.