# Minimum Number of Weigths

A wholesale merchant came to me one day and posed this problem. Every day in his business he has to weigh amounts from one pound to one hundred and twenty-one pounds, to the nearest pound. To do this, what is the minimum number of weights he needs and how heavy should each weight be?

The minimum number of weights required is five and these should weight 1, 3, 9, 27 and 81

pounds.

**[MODIFICATION]**

Explanation As per “BhaiBhai” comment-

For 2 Kg –

On one pan put 3 kg and on the other one put 1 kg

Likewise for 5 kg –

9 kg on one pan and 1+3 kg on another pan

For 6 kg – 9 on one and 3 on another

for 7 kg – 1 and 9 on one and 3 on another

for 8 kg – 9 on one pan and 1 on another.

how will you weight 2, 5,6,7,8??

according to me ans should be 7……1,2,4,8,16,32 and 64

Hey Friend,

For 2 Kg on one pan put 3 kg and on the other one put 1 kg

Likewise for 5 kg , 9 kg on one pan and 1+3 kg on another pan

for 6 kg,9 on one and 3 on another

for 7 kg, 1 and 9 on one and 3 on another

for 8 kg , 9 on one pan and 1 on another.

Think before you comment!!

How to weigh 15,16.. ?

For 15 kg – Put 27 kg on one and 9 kg +1 kg on other

For 16 kg – Put 27 kg on one and 9 kg on other

Great! How did you formulate this?

I am unable to get the exact answer.Can any one tell me the way of doing it??

it is something like

for 121= it lies between 3^1-3^4 so we consider 1,3^1,3^2,3^3,3^4.

similarly for 250 we will consider numbers from 3^1-3-5 i.e(1,3,9,27,81,243)

question says ‘to the nearest pound’, so shouldn’t we have 0.5 pound weight too? that way if something weighs 2.25 pound we will be able to measure it as 2 pounds. otherwise it will be heavier than 2 and lighter than 3 pounds and we wont be able to tell the nearest pound.

### Your Answer

## More puzzles to try-

### What is the logic behind these ?

3 + 3 = 3 5 + 4 = 4 1 + 0 = 3 2 + 3 = 4 ...Read More »### Five greedy pirates and gold coin distribution Puzzle

Five puzzleFry ship’s pirates have obtained 100 gold coins and have to divide up the loot. The pirates are all ...Read More »### Defective stack of coins puzzle

There are 10 stacks of 10 coins each. Each coin weights 10 gms. However, one stack of coins is defective ...Read More »### Dr. Willam and surgical gloves puzzle

Dr.Willam wants to operate for three different persons who were wounded. But he had only two surgical gloves. There is ...Read More »### Which clock works best?

Which clock works best? The one that loses a minute a day or the one that doesn’t work at all?Read More »### To which one will the needle touch 1 OR 2

In the gear arrangement, To which one will the needle touch, 1 OR 2Read More »### How did he know?

A man leaves his house in the morning to go to office and kisses his wife. In the evening on ...Read More »### Which letter replaces the question mark

Which letter replaces the question markRead More »### Crossing the Bridge Puzzle (Bridge and torch problem)

A bridge will collapse in 17 minutes. 4 people want to cross it before it will collapse. It is a ...Read More »### Probability of having boy

In a country where everyone wants a boy, each family continues having babies till they have a boy. After some ...Read More »### Magical flowers!!

A devotee goes to three temples, temple1, temple2 and temple3 one after the other. In front of each temple, there ...Read More »### How many times a day do all three hands of analog watch overlaps?

There is a perfectly accurate analog watch with hour, minute, and second hands. How many times a day do all three ...Read More »### Tuesday, Thursday what are other two days staring with T?

Four days are there which start with the letter ‘T‘. I can remember only two of them as “Tuesday , Thursday”. ...Read More »### How could only 3 apples left

Two fathers took their sons to a fruit stall. Each man and son bought an apple, But when they returned ...Read More »### How Many Eggs ?

A farmer is taking her eggs to the market in a cart, but she hits a pothole, which knocks over ...Read More »### Minimum number of persons needed to cross a Desert

In the middle of the confounded desert, there is the lost city of “Ash”. To reach it, you will have ...Read More »### Lateral thinking sequence Puzzle

Solve this logic sequence puzzle by the correct digit- 8080 = 6 1357 = 0 2022 = 1 1999 = ...Read More »### Pizza Cost Math Brain Teaser

Jasmine, Thibault, and Noah were having a night out and decided to order a pizza for $10. It turned out ...Read More »### Which room is safest puzzle

A murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, ...Read More »### Overthrow your math teacher!

Some numbers are very mysterious. They are all integers. They have more than one digit. If you multiply them with ...Read More »