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-
Guessing each other’s coins
You and a friend each has a fair coin. You can decide on a strategy and then play the following ...Read More »Lilypad’s size puzzle
A lilypad doubles in size each day. In 28 days, the lilypad will cover the entire pond. In how many ...Read More »Fence the Horses
The nine Horses are square fenced as shown in the picture below. By constructing just two square fences can you ...Read More »Describe your way of measuring the 45 minutes.
Your job is to measure 45 minutes, if you have only two cords and matches to light the cords. 1. ...Read More »Use the Homophones riddle
Use the homophones “to”, “too”, and “two” in one question.Read More »The Odd Ball
There are twelve identical-looking balls, but one is either heavier or lighter than the other eleven. How can you determine ...Read More »Black & Brown Stuff riddle
Filling these items with black/brown stuff I am sure you will be agreeing Ensures everyone in the office Starts the ...Read More »Howl & Whisper
You can feel it but, it can not feel you. It can uproot trees and tear roofs off. Yet, it ...Read More »Missing number puzzle
Can you find the missing number in the third row? 35 20 14 27 12 18 5 2 ...Read More »Calculate the area of the green region labeled as ‘?’
The below figure consists of a rectangle and the numbers labeled over the top represents the area of that particular ...Read More »Find the way riddle
I was traveling from Chesterton to Newcastle recently when I came across a sign which had fallen off its post ...Read More »Goat and Wolf Puzzle
A river. Shepherd wolf goat and a cabbage on one bank. Wolf wants to eat the goat wants the cabbage. ...Read More »People in Bus
You are on a bus. 10 people get on at the first stop. At the next stop 25 people get ...Read More »Ship in a Tub
A toy ship is floating in a cylindrical container 10 centimeters in diameter that is partially filled with water. How ...Read More »Number Games
Fill in the boxes with numbers from 1-10. One number can be used only once.Read More »Manholes round riddle
Why are manholes round?Read More »Sherlock shoots the pilot riddle
Detective Sherlock entered a restaurant, he heard a voice coming from the kitchen of the restaurant “No Andrew, Don’t shoot“. ...Read More »How will you write 6 times?
Assume 9 is twice 5; how will you write 6 times 5 in the same system of notation?Read More »Chelsea Player Statement
Eight Chelsea player makes the following statements : 1. Seven of us are lying here. 2. Six of us are ...Read More »How could the driver saw the dog puzzle
A completely black dog was strolling down main street during a total blackout affecting the entire town. Not a single ...Read More »