What can you serve, but never eat?

In a guessing game, five friends had to guess the exact numbers of apples in a covered basket.
Friends guessed 22, 24, 29, 33, and 38, but none of the guesses was correct. The guesses were off by 1, 8, 6, 3, and 8 (in random order).

Can you determine the number of apples in a basket from this information?

I always drive my customer away.

Who am I?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Thirty friends were on a hiking trip when they decided to enjoy the bonfire. They assembled for it and agreed to play a game. For that, they divided themselves into five teams with seven members each, forming five rows.

How did they manage to achieve this formation?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

Can you identify the hidden rebus in the image below?

One day, I thought of ways that can be used for creating a palindrome. So I decided that I will turn into a larger number by adding the reversed digits to the original number and keep doing it till I finally obtained a palindrome.

I am not sure if this process will always result in a palindrome eventually but I was able to produce a four-digit palindrome. Can you guess my starting number?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.