Question

Ten 50 paise coins: 6 tails, 4 heads. One coin is flipped randomly, seven times in total. One coin is covered. The rest show 5 tails and 4 heads. What does the covered coin show?

• A. a head
• B. a tail
• C. more likely a head
• D. more likely a tail

Hint:

Track total number of heads and tails before and after operations. If known counts match, the unknown is unchanged.

Answer 1

The Correct Option is A

Start: 6 tails, 4 heads → total 10 coins.
Each operation: pick 1 coin at random and flip it (change face). Do this 7 times.
After 7 flips, 1 coin is covered. Rest = 9 coins. These 9 show 5 tails and 4 heads.
So how many tails and heads in total? 5 + 4 = 9 covered coin contributes 1 unseen state.
We know: - Initial heads = 4 - Final heads visible = 4 - So covered coin must be a head (since total head count didn’t change).
\[ \boxed{\text{Head}} \]