NIELIT Scientist B 2020 November: 29

Question

 

A player rolls a die and receives the same number of rupees as the number of dots on the face that turns up. What should the player pay for each roll if he wants to make a profit of one rupee per throw of the die in the long run?

• A. ₹ $2.50$
• B. ₹ $2$
• C. ₹ $3.50$
• D. ₹ $4$

Answer 1

A player rolls a die and receives the same number of rupees as the number of dots on the face that turns up. That means if the player gets $2$ dots, then they will get $2$ rupees.

Expected value $= 1 \times \frac{1}{6} +2 \times \frac{1}{6}+ 3 \times \frac{1}{6} + 4 \times \frac{1}{6}  + 5 \times \frac{1}{6} + 6 \times \frac{1}{6}$

$= \dfrac{1+2+3+4+5+6}{6} = \dfrac{\frac{6(7)}{2}}{6} = \frac{21}{6} =$ ₹ $3.50$

On each roll of the dice, a player can expect to win $3.50 - 1 =$ ₹ $2.50.$

Correct Answer: A

Comments

@Lakshman Bhaiya Sir it is showing Math input error. Please fix this.

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fixed now 👍