#131 - Who Am I Math Puzzle

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

Who Am I Math Puzzle

DAVID

Talking in roman numerals,
D = 500
At the center is 5 = V
The first number is I
The first letter of the alphabet is A

Thus they combine to form DAVID.

#132 - Hard Number Riddle

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways ?

Hard Number Riddle

54
7^2 + 2^2 + 1^1
6^2 + 3^2 + 3^2
2^2 + 5^2 + 5^2

#133 - Famous Trivia Puzzle

Can you tell a 3D object that actually has just two surfaces?

Famous Trivia Puzzle

Did you think of paper?
Well that will be a wrong answer as a piece of paper has 6 surfaces as the edges are also counted as surfaces only no matter how thin they are.

The correct answer is a cone.

#134 - Tricky Math Logic Problem

A girl was fond of collecting rare stamps. When she was twenty years old, she bought a box to collect her stamps. On her every birthday, she put 250 stamps in it and her sister who was also fond of collecting stamps took out 50 stamps from it on her birthday. The girl met an accident when she was 60 years old. When her box was opened, there were only 500 stamps in it.

How is it possible logically?

Tricky Math Logic Problem

The girl was born on 29 February, thus she put 250 stamps every four years.
In forty years, she put stamps only 10 times which makes the total of 2500 stamps.
Her sister was born on any other day and she took out 50 stamps from the box forty times which makes the total stamp she took out to be 2000.

Thus after forty years, the girl’s box had only 500 stamps.

#135 - Tough Probability Interview Question

There is a country where everyone wants a boy. Every family continue to have babies till a boy is born. If the probability of having a girl or a boy is the same, what is the proportion of boys to girls after some time in that country?

Tough Probability Interview Question

Since the probability of having a girl or a boy is same, half of the families will have a boy first and stop. The other half of the families will have a girl and from half of those families, the second born will be a boy and they will stop while the others will again have a girl. This process will continue.

Suppose the number of couples are N, the number of boys will be N.

1/2 have a boy and stop: 0 girls
1/4 have a girl, then a boy: N/4 girls
1/8 have 2 girls, then a boy: 2*N/8 girls
1/16 have 3 girls, then a boy: 3*N/16 girls
1/32 have 4 girls, then a boy: 4*N/32 girls
…
Total: N boys and
1N 2N 3N 4N
– + – + – + — +… = ~N

Therefore the proportion of boys to girl will be quite close to 1:1.

#136 - Maths Logical Problem

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

Maths Logical Problem

Let us consider the length of the tunnel first; which is 200 miles. Now, the trains are running on the same speed which means that they will collide at the center of the tunnel and will take an hour to reach the center. Now the bird is travelling at a speed of 1000 mph and it is flying for an hour (since the trains will take an hour to collide). Thus the bird will travel 1000 miles in the process.

#137 - Challenging Math Equations Puzzle

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

Challenging Math Equations Puzzle

(0! + 0! + 0!)! = 6
(1 + 1 + 1)! = 6
2 + 2 + 2 = 6
3 x 3 - 3 = 6
√4 + √4 + √4 = 6
5 + 5/5 = 6
6 + 6 - 6 = 6
7 - 7/7 = 6
8 - √√(8 + 8) = 6
√(9 x 9) - √9 = 6

#138 - Maths Brain Twister Puzzle

A research team went to a village somewhere between the jungles of Africa. Luckily for them, they reached on the day when quite an interesting custom was to be performed. The custom was performed once in a year as they confirmed and was performed in order to collect the taxes from every male of the region.

The taxes were to be paid in the form of grains. Everyone must pay pounds of grain equaling his respective age. Which means a 20 year old will have to pay 20 pounds of grains and a 30 years old will pay 30 pounds of grain and so on.

The chief who collects the tax have 7 weights and a large 2 pan scale to weigh. But there is another custom that the chief can weigh only with three of the seven weights.

Can you find out the weights of the seven weights? Also what is the maximum age of the man that can be weighed for the payment of taxes ?

Maths Brain Twister Puzzle

There is a thing which you must keep in mind. The chief can put weights on both the pans.

Keeping that in mind
The weights 1, 3, 7, 12, 43, 76, 102
The oldest age that can be measured with these weights is 122

#139 - Maths Shopkeeper Problem

A brand new Beats Headphone was on sale at 20% as a promotional offer. By what percent must the headphone price be increased to sell it at the original price again ?

Maths Shopkeeper Problem

25%.
Suppose a $10 item is reduced by 20%, the price will drop to $8. Now to make it the original price we must add $2 more which is 25% of $8.

#140 - Riddle for Mathematician

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Riddle for Mathematician

XIX. On taking one i.e. I, we get XX i.e. 20