You have 9 marbles. 8 marbles weigh 1 ounce each, & one
marble weighs 1.5 ounces. You are unable to determine which
is the heavier marble by looking at them. You have a
weighing scale that consists of 2 pans, but the scale is
only good for 2 total weighings.
How can you determine which marble is the heaviest one using
the scale & in 2 weighings?
Answers were Sorted based on User's Feedback
Answer / guest
Divide 9 marbles into 3 groups of 3 marbles each.
Take any 2 groups and place them on each pan. If they
balance, remove the marbles from the pans, & place any 2 of
the marbles from the remaining unweighed group on the pans,
1 on each pan.
If one is heavier, it is the heavier marble, but if they
balance, the remaining unweighed marble is the heavier one.
If your first weighing does not balance, remove the marbles
from the lighter pan, & place 1 marble on each pan from the
heavier pan. The heavier 1 is the 1.5 ounce marble, but if
they balance, then the marble from the heavy pan from the
first weighing that was not weighed in the second weighing
is the heavy 1.
| Is This Answer Correct ? | 62 Yes | 5 No |
Answer / my name
Divide the 9 marbles into 3 groups: G1, G2, and G3. Weigh G1 with G2. If they balance, then the 1.5 ounce marble is in G3. Otherwise, the 1.5 ounce marble is in the heavier of G1 and G2.
Call the group that definitely contains the 1.5 ounce marble GS. Put one marble from GS in each pan. If they balance, the 1.5 is the member of GS not on a pan. Otherwise, it is the one in the pan on the heavier side.
| Is This Answer Correct ? | 20 Yes | 2 No |
Answer / siddarth chordia
The answer should be arrived in 2 weighings only with worst case scenarios to be considered...
So let us take 3 marbles in each pan
Step 1: If it weighs the same the heavier marble is in the other 3 marbles. else if it differs the heavier side in the balance has the heaver marbles.
Now we have 3 marbles to identify which is the heavier one...
Step 2: From the remaining 3 marbles, keep 1 marble in each pan. If it weighs the same, then the remaining one is the heavier, else which ever side on the balance weighs heavier then that is heavier.
Hope I hit the point of your question with only 2 weighings, to find the answer :)
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / dheeraj kumar
divide nine marbles into three groups, take any two group and
weight..
condition of scale will be ..
if both pans are same level then the heavy marble will be in
group that you left..
if not in same level then the heavier marble will be in group
in pan which has level down..
apply same procedure on the heavy group..
put two marbles on weighing scale, if both are on same level,
then left one is heavy marble, otherwise heavy one is the
marble which is on pan with level below than another...
| Is This Answer Correct ? | 4 Yes | 3 No |
Answer / hb
I will take 2 marbles on each pan, next time 2 marbles on
each pan. Now answer is
- If all the 8 marbles are weighed same, the heaviest
marble will be the one which is left.
- If in any of the two weighings,the heaviest marble is
will be on the pan which weighs more.
| Is This Answer Correct ? | 3 Yes | 7 No |
If a rook and a bishop of a standard chess set are randomly placed on a chessboard, what is the probability that one is attacking the other? Note that both are different colored pieces.
If you were to dial any 7 digits on a telephone in random order, what is the probability that you will dial your own phone number? Assume that your telephone number is 7-digits.
A fish had a tail as long as its head plus a quarter the lenght of its body. Its body was three-quarters of its total length. Its head was 4 inches long. What was the length of the fish?
You have 2 identical glass bulbs with you. Bulb manufacturer has mentioned that each bulb might withstand a drop of 200 Feet at maximum. Your task is to find the height at which the bulb breaks ofcourse with minimum number of iterations. Assume that you have 200 blocks of 1 foot each which can be stacked one by one to create a 200 Feet structure to carry out the test.
Imagine a triangle of coins on a table so that the first row has one coin in it and the second row has two coins in it and so on. If you can only move one coin at a time, how many moves does it take to make the triangle point the other way?
Given 3 jabs A,B,C with capacities 10L 8L 5 L You can get water from tap or pour away the water in the jar 1. How do you get 9L in jar A? 2. How do you get 7L in jar B?
To move a safe, two cylindrical steel bars 7 cms in diameter are used as rollers. How far will the safe move forward when the rollers have made one revolution?
A contractor had employed 100 labourers for a flyover construction task. He did not allow any woman to work without her husband. Also, atleast half the men working came with their wives. He paid five rupees per day to each man, four ruppes to each woman and one rupee to each child. He gave out 200 rupees every evening. How many men, women and children were working with the constructor?
Assume that you have just heard of a scandal and you are the first one to know. You pass it on to four person in a matter of 30 minutes. Each of these four in turn passes it to four other persons in the next 30 minutes and so on. How long it will take for everybody in the World to get to know the scandal?
Veeru says to Jay, "Can you figure out how many Eggs I have in my bucket?" He gives 3 clues to Jay: If the number of Eggs I have 1. is a multiple of 5, it is a number between 1 and 19 2. is not a multiple of 8, it is a number between 20 and 29 3. is not a multiple of 10, it is a number between 30 and 39 How many Eggs does Veeru have in his bucket?
A man is going to an Antique Car auction. All purchases must be paid for in cash. He goes to the bank and draws out $25,000. Since the man does not want to be seen carrying that much money, he places it in 15 evelopes numbered 1 through 15. Each envelope contains the least number of bills possible of any available US currency (i.e. no two tens in place of a twenty). At the auction he makes a successful bid of $8322 for a car. He hands the auctioneer envelopes number(s) 2, 8, and 14. After opening the envelopes the auctioneer finds exactly the right amount. How many ones did the auctioneer find in the envelopes?
In this four digit number, the second digit is half the third digit which is three less than the first which is six more than the fourth. If no digit is repeated, what is the number