Can you replace the question mark with the correct number?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

Can you decipher the below rebus?

PBLUESAISNUERSES

What does this rebus riddle mean?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

Can you find a five letter word that is left with only two letters if one is removed?