The result of rolling a fair die 150 times is as summarized in the table above. What is the probability of obtaining a 5?
- 3/10
-
1/5
- 1/6
- 1/10
The correct answer is: B
Explanation
Total possible outcome
12+18+x+30+2x+45 = 105+3x
∴105+3x = 150
3x = 150-105
3x = 45
x = 15
P(obtaining 5) = \(\frac{2x}{(105+3x)}But x= 15\\
=\frac{2(15)}{(105+3(15))}\\
=\frac{30}{(105+45)}\\
=\frac{30}{150}\\
=\frac{1}{5}\)
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