2, 3, 5, 9, 17, _ What is the next number in the sequence?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

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?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Solve the puzzle by telling what does below picture means.

Rob is taller than Edwin, and Jurgen is shorter than Rob.
Of only one of the following statements, we now certainly know it is correct:

A.Edwin is taller than Jurgen
B.Jurgen is taller than Edwin
C.It cannot be determined if Jurgen or Edwin is the tallest.

Why is the Hole below a Lock?

Why did the Girl throw the butter out of the window?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?