Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

O_er_t_o_

Complete the missing letters of the given word.

Check out the number list below and find what number comes next in the sequence.

111 , 113 , 117 , 119 , 123 , 137 , ?

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

Who am I?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

Give it food and it will live; give it water and it will die.