Question

The probability of getting 2 heads and 1 tail when three coins are tossed is 3 in 8. Find the odds of not getting 2 heads and 1 tail.

ANSWER: 5:8?

Three Coins are tossed. Find the probability that exactly 2 coins show heads if the first coin shows heads.?

ANSWERS: Could it be 1/4?

Answer 1

The first answer is correct.

For the second, once you have the first head there are four possibilities for the other two coins:

HH
TT
TH
HT

They must show one head for there to be two heads. What proportion do you find?

I hope this helps. Thanks for asking.

Answer 2

ANSWER :

Q1 :

Odds of not getting 2 heads and one tail = 1 - 3/8 = 5/8 

Suggested answer 5/8 is correct.

Q2.

First coin is hard, so the remaining two coins should show exactly one head.

Hence, 

P(2 coins show exactly one head)

= one coin head and another coin tail or one coin tail and another coin head

= 1/2 * 1/2 + 1/2 * 1/2

= 1/4 + 1/4 

= 1/2 

Hence,

Suggested answer 1/4  is not correct. It should be 1/2 (ANSWER).