Can you find the missing piece of the Porsche?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

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.

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

What 5-letter word typed in all capital letters can be read the same upside down?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

Divide 110 into two parts so that one will be 150 per cent of the other. What are the 2 numbers?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?