Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

Can you count the number of triangles inside a triangle?

A maths symbol is hidden in the below Bar Graph. Can you decipher it?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

Can you make a fire with just a single stick?

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

What does an Island and the letter T have in common?

I can write cow in 13 letters.

Can You?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?