Answer:
$350
Step-by-step explanation:
Your "20x + 30y = C(x, y)" formula is correct. For part b, you need to substitute 10 for x and 5 for y:
20(10) + 30(5) = C(10, 5) = 200 + 150 = 350 (all figures represent dollar amounts).
Kito's total July income was $350.
