9 coins you have, one of the coin has lesser weight, you have a weighing balance, how many times you will have to use that to pick out the lesser weighted coin?

Question

Accepted Answer

Answer is maximum number of times you need to use the weighing balance is 4 times. 
Logic: Weigh (1,1) coin on each side of the weighing balance. If the coins have same weight, the weighing balance will show equal weight and it will get balanced. If they are not, the weighing balance will be down on the side of the heavier coin and you'll come to know which coin is having a lesser weight. Repeat this process for max four times and you will come to know which coin is having a lesser weight. In this way it will cover or tell you the weights of 8 coins. If for all the above four occasions the weighting balance show equal weight, then the left out remaining coin (i.e. the 9th coin) is having a lesser weight.

Can someone validate whether the above answer is right or wrong.

Accepted Answer

ANS =2

Put a group of coins ( 3, 3 , 2).

weight (3,3) coins on either side of weighing machiene

either of two side will down or among that 2 coins 1 is heavier

lets suppose among 3 coins one is heavier then wieghs in group of (2,1) coins.

coins among that will be heavier if one side is down.

9 coins you have, one of the coin has lesser weight, you have a weighing balance, how many times you will have to use that to pick out the lesser weighted coin?

Top EXL Service Business Analyst interview questions & answers

Popular interview questions of Business Analyst

Top HR questions asked in EXL Service Business Analyst