I am an odd number. Take away a letter and I become even. What number am I?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

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?

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?

Which English verb becomes past tense just by rearranging the letters?

If eleven plus two equals one, what does nine plus five equal?

What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

It belongs to you, but other people use it more than you do. What is it?

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?