Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

John Went to the nearby store in a Mall to buy something for her home. Below is the conversation between the two:

John: How much for the one?
Shopkeeper: It is $2
John: How much for the Eleven?
Shopkeeper: It is $4
John: How much for the Hundred?
Shopkeeper: It is $6.

What is John buying?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

We can be boring,Or interesting.
We can be long,Or short.
We can have pictures,Or just words.
Many love us,But many also hate us.
What are we?

All of Jacob's shoes are red except two.
All of Jacob's shoes are green except two.
All of Jacob's shoes are yellow except two.

How many shoes does Jacob have?

I add 5 to 9 and get 2. The answer is correct, so what am I?