Why is a river so rich ?

In a box, there is a jumble of 7 red balls, 6 blue balls, 5 green balls, and 4 yellow balls. What is the minimum number of balls, will you have to pick up so that you have at least 4 balls of the same colour?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

The chance of Mr John winning the lottery is 10%. All participants lined up and Mr John is 4th in the row. The first three participants lose the lottery.

What is the chance of Mr John now?

How many letters are in the alphabet?

Lifeless eyes on my smiling face and watch your child's sleeping place. In their dreams they hold me tight. What am I?

Can you count the number of triangles in the picture below?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

You have a square. What you have to do is cut and reassemble the square such that you create a Red Cross sign that has the same volume as that of the square.

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?