What is next number in the pattern below:

131 517 192 123 ?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

After undergoing a successful eye operation, A blind girl has just boarded a train to her home. The doctor asked her to open the bandages after 3 hours. On her train journey, she opened the bandages and within a fraction of the time she commits suicide by jumping off the train.

Though her operation was successful, Why did she commit suicide?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

When a clock is observed, the hour hand is at a minute mark and the minutes hand is six minutes ahead of it.

When the clock is observed again after some time, the hour hand is precisely on a different minute mark and the minute hand is seven minutes ahead of it.

Can you calculate how much time has elapsed between the two observations?

10+10 and 11+11 can give you the same answer.

Explain how?

Which tank will fill first?

You can hear me, but you can't touch or see me.

What am I?

Which is the smallest number that you can write using all the vowels exactly once?

Why are all black people so quick ?