What does it mean?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

John bought a new car. He has a habit of eating ice cream from a particular ice cream shop while returning home from office. Whenever, he eats strawberry ice cream, he faces no problem. But whenever, he eats chocolate ice cream, the car starts giving problem. At first, he thinks, it is just a co-incidence but when this awkward incident happens for 3-4 times, he reports this problem to the company.

The mechanic of the company checks but finds no problem at all. The next day, when he stops by to eat chocolate ice cream, the car again starts giving problem.

Can you find the possible reason?

Solve the equation in the image by looking at the pattern closely.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

Which tank will fill first?

I have Rs.50 and I spend it in the way as below.

What is the below Rebus indicate?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

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