In 20 seconds without Pen & Paper you can solve Maths for JEE #shorts

There asre 5 questiions in a question paper. In how many ways can a boy solve one or more questions?

Can you produce sound without utillizing energy ?

Kandhan and Kavya are friends.Both of them are having some pens. Kandhan: If you give me one pen,then we will have equal number of pens.Will you? Kavya : But,if you give me one of your pens,then mine will be twice as yours Construct algebraic equations for this situation.Can you guess and find the actual number of pens,they have?