Probability
Probability
nta_abhyas_2025
Grade 12
Question:
Let the probability of getting any number other than 5 is P, then the probability of getting 5 is 5P. $P + P + P + P + 5P = 1$, P = $\frac{1}{9}$. Expected income per throw = $x imes (\frac{1}{9} + 8)$.
Step-by-Step Solution
Key Concept: Use the constraint that probabilities sum to 1, then apply expected value formula
Setting up the probability equation: $P + P + P + P + 5P = 1$ gives $P = \frac{1}{9}$, so the probability of rolling 5 is $\frac{5}{9}$. Expected income per throw = $x \times (\frac{1}{9} + 8) = x \times (\frac{1}{9} + \frac{8}{1})$. Using the given condition, the expected value calculates to 6.5.
Correct Answer: 1