Answer:
Derek's mango juice will last for 10 days.
Explanation:
Derek buys 5 small bottles of mango juice, so he has 5 bottles in total.
He plans to drink half the contents of each bottle every morning, which means he will drink 1/2 * 1 bottle = 1/2 bottle of mango juice every day.
Since Derek drinks 1/2 bottle of mango juice every day, the 5 bottles of mango juice will last for 5 bottles / (1/2 bottle per day) = 10 days.
So, the answer is that the 5 bottles of mango juice will last for 10 days.