What has many keys but can’t open a single lock?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?

Can you find the missing piece of the Porsche?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

If a wheel has 54 spokes, how many spaces are there between the spokes?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

What has one letter and starts with an E?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?