Rupee Coins
Written on 11:40 pm by Vja Students
A box contains two rupee coins. One is a double-headed coin, and the other is an ordinary coin, heads on one side, and tails on the other. You draw one of the coins from a box and look at one of the sides. Assuming it is heads, what is the probability that the other side shows heads also?
Ans:
When the coin is drawn, there are four possibilities, each of which is equally likely:
| Coin Drawn | Side Shown | Other Side |
| Double-Headed Coin | Heads | Heads |
| Double-Headed Coin | Heads (the other heads) | Heads |
| Ordinary Coin | Heads | Tails |
| Ordinary Coin | Tails | Heads |
The problem tells us that the last possibility did not occur. Therefore, there are three remaining possibilities, each of which is equally likely. Of the three, two of the possibilities will show heads on the other side; only one will show tails on the other side. So the probability that the other side of the coin is heads is two thirds.
The other side should be Heads or Tails......the probabiliy should be 1/2.
should be 2 in 3.
1- first head of the double headed coin
2- second head of the double headed coin
3- head of the single headed coin
1 and 2 will get heads on the other side
3 will get tails on the other side
so chance of heads on the other side is 2 in 3.
dr jayachandran t
it a simple question of bayes rule
you apply the prob of getting the head with the biased coin divided by the prob of getting the head from both the coin.....
1/(1+.5)=.66
I agree with manish it has to be half since they already asked to assume one side you saw is head
it's totally false answer
if you will pick one coin with
a head than other must be either
head or tail.
so the probability to be a head
is just 1/2.