(i)[3]
Find the probability that, on a day chosen at random, the company records a profit between $\$10\,000$ and $\$12\,000$.
(ii)[4]
Find the probability that the company makes a loss on exactly $1$ of the next $4$ consecutive days.
Mathematics 9709 · AS & A Level · Continuous random variables
Continuous random variables — practice question
The random variable $X$ represents the company's daily profit, measured in thousands of dollars. It has a normal distribution with mean $6.4$ and standard deviation $5.2$.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “By standardising, obtain $z_1 = \frac{12-6.4}{5.2}$ and $z_2 = \frac{10-6.4}{5.2}$” …
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