Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

Buy me, smell me or deliver me, I do not change.

Who am I?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

What part of the chicken has the most feathers?

What is the riddle which can be asked all day with a different correct answer each time.

Find the missing number in the sequence below:

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

Find three numbers such that When we multiply three numbers, we will get the prime numbers. The difference between the second and the first number is equal to the third and second.