How can you make number one disappear by adding something to it?

What does below chemistry rebus means?

You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?

You have two rectangular wires.

Both of them have property that when you light the fire from one end , it will take 60 minutes to get completely burn.

However, they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could you measure 45 minutes ?

John was piloting a plane behind a car but was never able to overtake it. Why?

Cristina leaves home and then she makes exactly 3 left turns and returns home where she found 2 girls wearing the mask.

Who are these two masked girls?

What does below rebus means ?

Can you identify the hidden rebus in the image below?

What does the below rebus riddle means?

Find out the missing number in the picture attached: