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

Using mathematical symbols like +, -, and x in order to make the equations correct. Replace # with the above-given symbols.

9 # 8 # 7 # 6 # 5 # 4 = 91

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Count the number of balls in picture below:

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?