Question

A magician has 10 coins in his pocket. Eight of these coins are normal fair coins (with one head and one tail) and two are defective coins with heads on both sides. The magician randomly draws a coin from his pocket and flips it. Given that the flipped coin shows a head, what is the probability that it is defective?

Answer 1

Answer:

1/3

Step-by-step explanation:

8 Fair coins

2 Defective coins

Probability of head from Fair Coins =   (8/10)(1/2)   = 2/5

Probability of Head from Defective coins =  2/10  =  1/5

Total Probability of Head  = 2/5 + 1/5  = 3/5

As we know that it is already Head  

then probability of being from defective coins  =  Probability of Head from defective coins / Probability of head

=>then probability of being from defective coins  = (1/5)/(3/5)

= 1/3