Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

Find the next number in the series below.

6 18 270 72090 ?

What has many teeth, but cannot bite?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

I drive at an average speed of 30 miles per hour to the railroad station each morning and catch my train. On a particular morning, there was a lot of traffic and at the halfway point, I had averaged only 15 miles per hour. How fast must I drive for the rest of the way to catch my train?

You are a cab driver who pools passengers. You pick 3 people from a destination and drop 1 after an hour. 2 people climb aboard at the same time and you drop 3 at the next destination. After some time, you pick 2 passengers only to drop 1 after a short distance where 3 more passengers climb up the cab. You leave the rest of the passengers one by one to their destination and then come back home.

Can you tell the eye color of the cab driver?

One day, I thought of ways that can be used for creating a palindrome. So I decided that I will turn into a larger number by adding the reversed digits to the original number and keep doing it till I finally obtained a palindrome.

I am not sure if this process will always result in a palindrome eventually but I was able to produce a four-digit palindrome. Can you guess my starting number?