What does below chemistry rebus means?

You see me once in June, twice in November, and not at all in May. What am I?

Trying to tease Birbal, Akbar gave him one gold coin and ask him to buy
* something for him to eat
* something for him to drink.
* something to feed the cows
* something to plant in the garden
and most important you need to buy only one thing.

What must Birbal buy to silence Akbar?

Replace The Question Mark Below With the Correct Number.

2 {38} 3
4 {1524} 5
6 {3548} 7
8 {????} 9

What does this mathematical rebus means ?

In a classic wine shop, the list of three most popular wines are:
- The cost of 1 French wine bottle: 500$
- The cost of 1 German wine bottle: 100$
- The cost of 20 Dutch wine bottles: 100$

John entered the wine shop and he needs to buy
- All three types of wine bottles.
- Needs to buy Dutch wine bottles in multiples of 20.
- Need to buy 100 wine bottles in total.

John has only 10000$. How many wine bottles of each type, John must buy?

What does this rebus puzzle means ?

Can you fill the blank with the correct number?

6 30 870 756030 _____

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

If two's company, and three's a crowd, then whats four and five ?