Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

John can place six large boxes or nine small boxes into a carton.

Can you find out in how many cartons can he place sixty-six boxes in total?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

What does the below rebus riddle means?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

A man is walking down a road with a basket of eggs. As he
is walking he meets someone who buys one-half of his eggs
plus one-half of an egg.
He walks a little further and meets another person who buys
one-half of his eggs plus one-half of an egg.
After proceeding further he meets another person who buys
one-half of his eggs plus one half an egg. At this point, he
has sold all of his eggs, and he never broke an egg.
How many eggs did the man have to start with?

Using Only Five 5's and any mathematical operator make sum as 37

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?