Question

A throws a coin $3$ times. If he get a head all three times, he is to get a reward of Rs.$200$, on the other hand if he does not get $3$ heads he is to loose Rs.40. He is expected to win Rs. ...............

• A. Rs. $50$
• B. Rs. $(-10)$
• C. Rs. $35$
• D. Rs. $10$

Answer 1

Answer: (B)

Rs. $(-10)$

A throw of $3$ coins, total probability $=8$

$\Rightarrow$ Probability of getting head on all three throws $=\frac{1}{8}$

$\Rightarrow$ Probability of not getting head on all three throws $=\frac{7}{8}$

$\therefore \frac{7}{8}\times 40=35$

$\Rightarrow 35-(40+5)=Rs.(-10)$

Hence, the answer is $Rs.(-10).$