Question 50

Jambmaths question: 

The result of rolling a fair die 150 times is as summarized in the table below

Number

1

2

3

4

5

6

Frequency

12

18

x

30

2x

45

What is the probability of obtaining a 5?

Option A: 

$\tfrac{3}{10}$

Option B: 

$\tfrac{1}{5}$

Option C: 

$\tfrac{1}{6}$

Option D: 

$\tfrac{1}{10}$

Jamb Maths Solution: 

$\begin{align}  & freq=150 \\ & 12+18+x+30+2x+45=150 \\ & 105+3x=150 \\ & 3x=45 \\ & x=15 \\ & prob=\frac{no\text{ }of\text{ expected outcome}}{\text{total number of possible outcome}} \\ & prob\text{ }of5=\frac{2(15)}{150}=\frac{30}{150}=\frac{1}{5} \\\end{align}$

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