Math Puzzles - 3

Puzzle - 1: ( ) + ( ) + ( ) + ( ) + ( ) = 30.

This is what you have for equation. The following are the numbers that you can use to fill in the brackets:

1, 3, 5, 7, 9, 11, 13 and 15

You can repeat the numbers if required. The resulting sum should be 30

Puzzle - 2: assuming i have an infinite supply of coins.

What is the fewest number of coins would be required in order to make sure each and every coin touched exactly three other coins.

Puzzle - 3:  By using only one straight line, can you make the equation correct.

5+5+5=550?

Puzzle - 4: On a magical-intellectual land of puzzles, all the animal are rational (real smart).

There are six leopards and one sheep. Leopard can eat sheep but since as the land is magical, the leopards who eats the sheep, turns into sheep and then can be eaten by the remaining leopard(s).

If we leave them for some time then how many sheep and leopard will be there, when we come back?

Puzzle - 5: Which number replaces the question mark?

3 + 5 + 6 = 151872

5 + 5 + 6 = 253094

5 + 6 + 7 = 303585

5 + 5 + 3 = 251573

Then 9 + 4 + 7 =?