Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Five lovely ladies(Sophia, Isabella, Madison, Emma and Olivia) planned a picnic.

They each buy one thing each for the picnic.

Sophia, Emma and Olivia got a drink : orange-Juice, apple-juice, and mango-juice.
Olivia got the drink with the same letter as the one in her first name.
Emma loves mango-juice.
The other two bring some food : chocolates and pizza.
Also Madison is allergic to cheese.

So which ladies bought what ?

There are forty elephants and they have forty-fore heads. How can this be possible?

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

what does this below rebus represent identXQQQQQME

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

Which is faster, Heat or Cold ? Explain.

If eleven plus two equals one, what does nine plus five equal?

Can you find out the remainder when 3^300 is divided by 5?