Questions

The logic in the given puzzle is 

4 + 4 = 4 * 4+1 = 4 * 5 = 20

5 + 5 = 5 * 5+1 = 5 * 6 = 30

6 + 6 = 6 * 6+1 = 6 * 7 = 42

7 + 7 = 7 * 7+1 = 7 * 8 = 56

Similarly

9 + 9 = 9 * 9+1 = 9 * 10 = 90.

Entropy is a measure of disorder . It will be maximum in gases followed by liquids and least in solids.

Hence, here the gas is only hydrogen and it has the highest entropy.

Apple briefly touched $800 billion market valuation, making it the world's first ever company to hit the milestone. At $800 billion, Apple's valuation was higher than the combined market cap of all the 30 Sensex companies, which stood at $784 billion. The world's most valuable company, Apple is followed by Google parent Alphabet, and Microsoft in market valuation.

The missing number in the given number puzzle is "78".

Here the logic is the numbers are from 86 - 91 when we read upside down.