Can you start the fire using two pieces of wood?

Next Number in the Series,

5, 16, 49, 104, ?

In a school, 280 students studied chemistry, 254 students studied physics and 280 students studied biology.

97 students studied chemistry as well as physics, 138 students studied physics as well as biology and 152 students studied chemistry as well as biology.

73 students studied all the three branches.

Can you find out the total number of students?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

Move four matchsticks to the below square to form three squares?

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

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?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

What building has the most stories?