If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

I am white when I am dirty, and black when I am clean. What am I?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?

What can you see in the middle of March and April that you can never see in any other month?

What type of tree can I carry in my hand?

Sally lives in a place where six months of the year is mild summer and the temperature drops significantly the other six months. She owns a lake where there is a small island. She wants to build a house on the island and needs to get materials there. She doesn’t have a boat, plane, or anything to transport them to the island. How does Sally solve this problem?

Three ants are sitting at the three corners of an equilateral triangle. Each ant starts randomly picks a direction and starts to move along the edge of the triangle. What is the probability that none of the ants collide?