Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?

What's a single-digit number with no value?

Find out the missing number in the picture attached:

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Which tank will fill first?

How many times do a clock's hands overlap in a day ?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?