you gotta count the individual bananas not bundle by bundle. so one bundle of bananas has 4 bananas meaning 4 + 4 bananas + 1 apple (which equals to 10) gives 18.
the final question is 1 coconut (2) + 1 apple (10) + 3 bananas (one individual banana is 1) so the final answer is 15 because 2 + 10 + 3 = 15
i struggled too but if you answer wrong once the game gives a hint that says "count the bananas" or something like that they just mean every banana in each bundle