# River Crossing with one Torch

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

# Similar Riddles

##### Black Changes its Colour

What is black when you buy it, red when you use it, and gray when you throw it away?

Asked by Neha on 06 Jan 2021

##### Become Millionaire

A kind heart person buy packed food at 3\$/packet from United states and sells them at 1\$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

Asked by Neha on 30 Jan 2023
##### Apple in the Basket

You have a basket containing ten apples. You have ten friends, who each desire an apple. You give each of your friends one apple.
Now all your friends have one apple each, yet there is an apple remaining in the basket.
How?

Asked by Neha on 18 Sep 2021

##### Pints of beer

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

Asked by Neha on 26 Feb 2023
##### Dice Game with Math

On rolling two dices (six-sided normal dice) together, what is the probability that the first one comes up with a 2 and the second one comes up with a 5?

Asked by Neha on 08 Oct 2023
##### Trapped in Ice Lake

Suppose that you are trapped on the surface of a frozen lake. The surface is so smooth and ideal that there is no friction at all. You cant make any grip on the ice and no wind is blowing to help you out. You have just a mobile phone with you which has got no reception disabling you to call for help.

How will you plan your escape before you freeze to death on the frozen lake?

Asked by Neha on 25 Dec 2020

##### Find the Colour

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

Asked by Neha on 27 Feb 2021
##### Unususal Paragraph

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary, you'd think nothing was wrong with it. Actually, nothing IS wrong with it. But it is not as ordinary as you might think. If you think about it for a bit, you will find out why it is truly so unusual. So what is it? What is so unordinary about this paragraph?

Asked by Neha on 02 May 2022
##### Servants with multiple legs

The king of Octopuses has servants who have six, seven or eight legs. The distinguishing characteristics of the servants is that the one with seven legs always lie but the one with either six or eight legs speak the truth always.

One day, four servants meet and converse:

The black one says, 'We have 28 legs altogether.'

The green one says, 'We have 27 legs altogether.'

The yellow one says, 'We have 26 legs altogether.'

The red one says, 'We have 25 legs altogether.'

Can you identify the colour of the servant who is speaking the truth?

Asked by Neha on 09 Apr 2021

##### English Statement

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

Asked by Neha on 10 Mar 2024

### Amazing Facts

###### Rubik’s Cube

The inventor of the Rubik’s Cube didn’t realize he’d built a puzzle until he scrambled it the first time and tried to restore it.