How is a fly different from a mosquito?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

Find the smallest sentence with all the English alphabet.

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Can you solve the below tricky visual equation?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

What is the probability of choosing the correct answer at random from the options below?

a) 1/4
b) 1/2
c) 1
d) 1/4

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?

A man always keeps a spare tyre in his car. To make full use of all the five tyres, he changes the tyres in a manner that for a distance of 1, 00,000 km, each of them runs the same distance.

Can you calculate the distance travelled by each tyre on that journey?

Can you spot the hidden girl in the picture below?