Using Only Five 5's and any mathematical operator make sum as 37

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

An express train takes 3 seconds to enter the tunnel which is 1 km long.
If it is travelling at 120 km an hour, how long will it take to pass completely through the tunnel?

There is a number which when you multiply by 3 and subtract 2 from the result, then the resulting number is the reverse of the actual number.

What is the smallest number that stands true on the statement?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

A rain drop fell from one leaf to another leaf and lost 1/4th of its volume. It then fell to another leaf and lost 1/5th of the volume. It again fell on another leaf and lost 1/5th of the volume.



This process kept repeating till it fell on the last leaf losing 1/75th of its volume.



Can you calculate the total percentage of loss from the initial volume when the drop has fallen to the last leaf accurate up to two decimal places?

You have two jars of chocolates labelled as P and Q. If you move one chocolate from P to Q, the number of chocolates on B will become twice the number of chocolates in A. If you move one chocolate from Q to P, the number of chocolates in both the jars will become equal.

Can you find out how many chocolates are there in P and Q respectively?

What is next number in the pattern below:

131 517 192 123 ?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?