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

which number am I?

How many triangles are there on the puzzle below?

My grandson is about as many days as my son in weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 120 years. Can you tell me my age in years ?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

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

A little girl goes to the store and buys one dozen eggs. As she is going home, all but three break. How many eggs are left unbroken?