A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

John and Jenni are a married couple. They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

Rihana, Peeta, and Logan order a pizza for $10. Out of the three, Rihana and Peeta were quite hungry and ate 6 slices a piece, while Logan had just 2 slices.

Now, they want to split the cost among them fairly but due to the lack of change, they decide to round off the cost to the nearest possible dollar.

Can you find out the fairway which should be used to split the money?

What if the pizza was worth $11?

John and Jacob are playing bets. John gives $10 to Jacob and Jacob deals four cards out of a normal 52-card deck which are chosen by him completely randomly. Jacob keeps them facing down takes the first card and shows it to John. John has a choice of either keeping it or looking at the second card. When the second card is shown to him, he again has the choice of keeping or looking at the third which is followed by the third card as well; only if he does not want the third card, he will have to keep the fourth card.

If the card that John is choosing is n, Jacob will give it to him. Then the cards will be shuffled and the game will be played repeatedly. Now you might think that it all depends on chance, but John has come up with a strategy that will help him turn the favor in his odds.

Can you deduce the strategy of John?

You need to cut a round cake into eight equal pieces with just 3 cuts. Can you do it?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

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?

In an Art Gallary, When the clock hit 11 am, Artist hung the painting number 30. When it struck 4 pm, he hung painting number 240 and when it struck 7:30 pm, he hung painting number 315.

Can you determine, which painting number will he hang when the time is 9:20 pm?

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?