Why is the Hole below a Lock?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

In particular commonwealth games, a female participant won silver and gold medals for a single event.

How can this be possible?

A Car is crossing a bridge 2 miles long. The bridge can only hold 10000 lbs, which is the exact weight of the car. The Car makes it half way across the bridge and stops. A bird lands on the car. Does the bridge collapse? Explain.

Two natural numbers have a sum of less than 100 and are greater than one.

John knows the product of the numbers and Jacob knows the sum of numbers.

The following conversation takes place between them:
John: 'I am not aware of those numbers.'
Jacob: 'I knew you wouldn't be. I am not aware myself.'
John: 'Now I know them!'
Jacob: 'Now I know them, too!'

What are the two numbers?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

Identify The phrase in the picture.

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?