Answer:
8(3)+5(3)=40
Explanation:
Start with 8(x)+5(y)=40
Next note that if you times them by each other you get 40
now knowing you can't have it over 5 for either helps you know you shouldn't have more than 4 either
knowing that 3 is the best option for both
If you not that 8 and 5 are both not prime you can get 40 exactly