Answer: 5:10 or 1:2
Step-by-step explanation: Looking at the problem, they're asking you to figure out the ratio, in the form of bananas (I'll use b), to apples (I'll use a). With that in mind, just substitute the values, in that exact order, into the equation. Since b=5 (there are 5 bananas), and a=10 (there are 10 apples), and the ratio is b:a, you could put 5:10, or simplify it (only if they ask) to 1:2. For future reference, make sure to pay very close attention to the order of the ratio they're asking you for, as this could be the difference between a correct answer and a 0.
Hope this helps,
Lacia :))