Can you find the odd number in the following?

2716, 4135, 5321 and 7145

How can you take 2 from 5 and leave 4?

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

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

John needs to purchase 100 chocolates from three different shops and he has exactly 100 rupees to do that which he must spend entirely. He must buy at least 1 Chocolate from each shop.

The first shop is selling each chocolate at 5 paise, the second is selling at 1 rupee and the third is selling at 5 rupees.

How many chocolates should he buy from each shop?

Why do we preferably have round manhole covers and not square ones?

Can you find out the total number of triangles in the given figure?

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?