There are 9 coins. Out of which one is odd one i.e weight
is less or more. How many iterations of weighing are
required to find odd coin?

Answer Posted / abhishek gupta

[REQUEST- PLEASE READ IT ATLEAST TWICE]

4 ITERATIONS OF WEIGHING....
DIVIDE THE 9 COINS INTO 3 BATCHES (4, 4 AND 1).

1) FIRST WEIGH THE FIRST BATCH WITH THE SECOND ONE. IF THE
BALANCE DOESN'T SHOW ANY MOVEMENT, THEN THE LEFT OUT COIN IS
THE ODD COIN.

2) IF THERE IS ANY MOVEMENT, THEN TEST THE 2 BATCHES
INDIVIDUALLY, i.e., 2 ON EACH SIDE OF THE BALANCE FOR BOTH
THE BATCHES. OUT OF THE 2 BATCHES, 1 WOULD SHOW MOVEMENT.
THEN IT IS CLEAR THAT THE ODD COIN IS FROM EITHER OF THE 4
COINS (SAY, THE SECOND BATCH).

3) [A] THEN, BALANCE ANY 2 COINS FROM THE SECOND BATCH
(HAVING THE ODD COIN) WITH 2 FROM THE FIRST BATCH (NOT
HAVING ANY ODD COIN).

4) IF THE BALANCE SHOWS ANY MOVEMENT, THEN AGAIN BALANCE 2
COINS (1 OF SECOND BATCH FROM THE BALANCE + 1 FROM THE FIRST
BATCH) WITH 2 MORE COINS FROM THE FIRST BATCH. IF THE
BALANCE DOESN'T SHOW ANY MOVEMENT, THEN THE LEFT OUT COIN ON
THE BALANCE [A] OF SECOND BATCH IS THE ODD ONE. BUT IF THE
BALANCE SHOWS SOME MOVEMENT THEN THE COIN WHICH WE TOOK OF
SECOND BATCH FROM THE BALANCE [A] IS THE ODD ONE OUT.

NOTE--- IN ALL OTHER ANSWERS, YOU ARE NOT ABLE TO FIND "THE
1 ODD COIN" TILL THE STEP. BUT HERE YOU GET IT CORRECT IN
ANY WAY, IN MAX-4 STEPS AND NOT 9 STEPS.

Is This Answer Correct ?    3 Yes 21 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Three containers A, B and C have volumes a, b, and c respectively; and container A is full of water while the other two are empty. If from container A water is poured into container B which becomes 1/3 full, and into container C which becomes 1/2 full, how much water is left in container A?

1135


Find the next series number : 21, 463, 687, 238, 1134, ----

651


An article sold at a profit of 20% if both the cost price and selling price would be Rs.20/- the profit would be 10% more. What is the cost price of that article?

821


A person travels 12 km in the southward direction and then travels 5km to the right and then travels 15km toward the right and finally travels 5km towards the east, how far is he from his starting place?

760


complete the series: a c b d f e g i __

1041






1/3 rd of the contents of a container evaporated on the 1 st day. 3/4 th of the remaining contents of the container evaporated the second day. what part of the contents of the container are left at the end of the second day.

788


In a company 30% are supervisors and 40% employees are male if 60% of supervisors are male. What is the probability that a randomly chosen employee is a male or female?

1297


five cities. city1 is west to city3. city4 is east to city 5.__ etc.which is farthest on west side.

3334


Bird is flying 120km/hr b/w b to r. Two trains at b to r at 60 kmph the distance traveled by the bird before it is killed.

758


There are 5 red shoes, 4 green shoes. If one draw randomly a shoe what is the probability of getting red shoe

871


a man purchased 6 stamps of rupees 1 and seven stamps of 50 paise.he paid Rs. 12. how much change he got back ?

759


The ratio of length of a rod and its shadow is 1/sqrt(3). Find the angle of elevation.

836


4i+8j+10k. something like this.

6261


Three independent mechanisms A, B and C have been incorporated for power saving in a plant producing respectively 30%, 40% and 10% efficiency. Assuming that they operate independently, what is the net power efficiency achieved

2203


The minimum token cost is Rs. 100, which grants the token holder to travel up to a distance of 10 miles. And for every additional mile travelled, the charge is Rs. 10. A minimum luggage weight of 10 kg is not charged, after which it is charged at Rs. 1 per kg. During a specific journey, suppose you carry a weight of 'k' kg, and a distance of 'p' miles is travelled, which equation will indicate the correct total charge to be paid by the traveller?

700