Question

YOU HAVE 8 COINS IN A BAG. 3 OF THEM ARE UNFAIR AND THEY HAVE 60% CHANCE OF COMING UP WITH HEAD WHEN FLIPPED. YOU RANDOMLY CHOSE ONE COIN FROM THE BAG AND FLIP IT TWO TIMES. WHAT IS THE PROBABILITY OF GETTING TWO HEADS?

Answer 1

0.29125 or 29.125%

Explanation:

For the five fair coins, the probability of coming up head when flipped is 0.5, so for two flips: 0.5*0.5 = 0.25, for each of these coins. So, the probability to take on of them is 5/8, and the probability of coming up with head: (5/8)*0.25 = 0.15625.

For the unfair coins, the probability of coming up with heads is 0.6, so for two flips: 0.6*0.6 = 0.36 for each unfair coins. The probability to chose one of them is 3/8, and the probability of coming up with head: (3/8)*0.36 = 0.135.

These probabilities are dependent, so to have the total probability we must sum them:

P = 0.15625 + 0.135

P = 0.29125 or

P = 0.29125 x 100% = 29.125%