Question

Suppose you roll a special 10-sided die. What is the probability that the number rolled is a "8" OR a "9"? Enter you answer as a fraction or a decimal with 3 decimal digits.

Answer 1

• 1/5 or 0.2

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Each number from 1 to 10 has same probability of 1/10.

So we have 1/10 for an '8' and 1/10 for a '9'.

The probability of either '8' or '9' is the sum of the two probabilities:

• P(8 or 9) = 1/10 + 1/10 = 2/10 = 1/5 = 0.2