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 / samveg gupta
It is always possible to find odd coin in 3 weighings and to tell whether the odd coin is heavier or lighter.
1. Take 8 coins and weigh 4 against 4.
o If both are not equal, goto step 2
o If both are equal, goto step 3
2. One of these 8 coins is the odd one. Name the coins on heavier side of the scale as H1, H2, H3 and H4. Similarly, name the coins on the lighter side of the scale as L1, L2, L3 and L4. Either one of H's is heavier or one of L's is lighter. Weigh (H1, H2, L1) against (H3, H4, X) where X is one coin remaining in intial weighing.
o If both are equal, one of L2, L3, L4 is lighter. Weigh L2 against L3.
 If both are equal, L4 is the odd coin and is lighter.
 If L2 is light, L2 is the odd coin and is lighter.
 If L3 is light, L3 is the odd coin and is lighter.
o If (H1, H2, L1) is heavier side on the scale, either H1 or H2 is heavier. Weight H1 against H2
 If both are equal, there is some error.
 If H1 is heavy, H1 is the odd coin and is heavier.
 If H2 is heavy, H2 is the odd coin and is heavier.
o If (H3, H4, X) is heavier side on the scale, either H3 or H4 is heavier or L1 is lighter. Weight H3 against H4
 If both are equal, L1 is the odd coin and is lighter.
 If H3 is heavy, H3 is the odd coin and is heavier.
 If H4 is heavy, H4 is the odd coin and is heavier.
3. The remaining coin X is the odd one. Weigh X against the anyone coin used in initial weighing.
o If both are equal, there is some error.
o If X is heavy, X is the odd coin and is heavier.
o If X is light, X is the odd coin and is lighter.
Is This Answer Correct ? | 10 Yes | 1 No |
Post New Answer View All Answers
write a five digit number , which will be having two prime numbers, and some two more conditions,like 1st digit greater than 2nd etc its easy(remember one is not a prime number,most people don mistake taking 1 as prime number)
What is the probability of getting 3 or 4 in 3 consecutive rolls of a dice ?
quants,logical,verbal
What number should be added to or subtracted from each term of the ratio 17 : 24 so that it becomes equal to 1 : 2.
maths
A triangle has sides of lengths 10, 24 and k. k is a positive integer. The number of values of k for which this triangle has three acute angles is
A team P of 20 engineers can complete a task in 32 days. Another team Q of 16 engineers can complete the same task in 30 days. Then the ratio of working capacity of 1 member of P to that of a member of Q is:
Two people X & Y walk on the wall of a go down in opposite direction. They meet at a point on one side and then go ahead. X after walking for some time, walks in opposite direction for 15 mtrs.Then again he turns back and walks in the original direction. What distance did Y walk before they met again, if X walks 11 mtrs by the time Y walks 8 mtrs.
Cost of an item is Rs 12.60 ,profit is 10% over selling price.
In school there are some bicycles and 4 wheeler wagons. One tuesday there are 190 wheels in the campus. How many bicycles are there?
How can you make a square from two triangles?
If INDIA = JOEJB then BSNZ =?
Distance d=rt where r & t are positive and r is constant,as t increases then d_________
what is the angle between two hands of a clock when time is 8-30
Fill the empty slots. Three FOOTBALL teams are there. Given below the list of maches. played won lost draw Goals for Goals against A 2 2 *0 *0 *7 1 B 2 *0 *1 1 2 4 C 2 *0 *1 *1 3 7 the slots with stars are answers.