Scientists were trying out a new lie detection test based on a needle. The needle indicates red if it a lie and green if it’s true. For any person lying, there is a 75% chance of the needle pointing towards red. For a person not lying, there is a 90% chance of the needle pointing towards green. It is known that 10% of people who go for the test are lying.

If a person who tests to have lied, If the probability that they actually lied is P, then 11P equals?​

There are a mix of red, green and yellow balls in a bag. The total number of balls is 60. There are four times as many red balls as green, and six more yellow balls than green balls. How many balls of each color are there?

Cow’s milk has 5% fat. How much milk without fat should be added to 40 liters of cow’s milk to get 4% fat?

Fill in the above matrix boxes so that the 1st, 3rd and 5th row is 20, 48 and 38 respectively while the 1st, 3rd and 5th column is 0, 80 and 10.

☐ + ☐ = 8

 X                 |

☐ x  ☐ = 9

||                ||

21                5

B + ( B/4 ) * 7 + [( B*2 ) – ( B-2 ) ( B-2 )] + 5 – ( B*B ) = B

What is the value of B?

Puzzle by : Pranav Tambat

somewhere in the wonder land there are sequence of 7 Temples separated by 7 rivers,
Sequence is Temple, River, Temple, River…………
A man has to put equal number of flowers on every temple but the catch is as he crossed the river, remaining flowers will be doubled (2 times)

how many flowers should a man carry with him before entering into first temple so that till last river he has left with nothing?

Assume he took 5 flowers,
on first temple he drop 2, remaining is 3 as he crossed the river it will become 6, he put same number of flowers (i.e 2 flowers) 6-2=4 which again become twice in second river means 8…

I tried so many ways but cant get the answer?
Hope someone else come up with some good logical based answer

A mother has twelve children, each born in a different month. They want to go to the beach. She says she’ll take them if they can win a game. She puts the name of each child on a card and tells them she will place the cards face-down in a row on a table in the next room.

She’ll randomly call one child in. The child can turn over cards one at a time, up to half the cards, looking for his or her own name.

If that child finds his or her own name, he or she will be sent outside to play, and won’t be able to communicate with the children still waiting to take a turn. The mother will turn all the cards back face-down, keeping them in the same order, and will randomly call in another child and repeat the process. In order for the children to win the game and go to the beach, all the children must be successful in finding their own names. If any child fails, the game is over, and there will be no trip to the beach! The children can consult each other before their mother starts the game, but those who have already taken a turn cannot contact the others or leave any clues for them.

The children talk among themselves and devise a strategy that all the children will be able to follow perfectly. The game begins, and the first child is called into the room where the game is taking place. A few minutes later, he comes back into the room with the other children, grinning widely. “Pack your swimsuits and your towels!” he says. “We’re going to the beach!”

The child is correct, and knows for certain that the inevitable outcome of the game is that the children will win. How many cards did he turn over before he found his name?

puzzle by Harvey Lerman