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A student was doing a project work, involving a school survey, to find the number of hours spent on study by students, on a randomly selected school day. At the end of the survey he prepared the following report related to the data.

Let x denote the number of hours spent on study by students on a randomly selected school day

then,

P(X=x)={0.2,if x=0kx,if x=1 or x=2k(6−x),if x=3 or x=40,otherwiseP(X = x) = \begin{cases} 0.2, & \text{if } x = 0 \\ kx, & \text{if } x = 1 \text{ or } x = 2 \\ k(6-x), & \text{if } x = 3 \text{ or } x = 4 \\ 0, & \text{otherwise} \end{cases}

where k is unknown constant

Based on the above information answer the Questions

The probability that the study time of students is at least 3 hours

Solution

✅ Correct Option: 1

P(X≥3)=P(X=3)+P(X=4)=3k+2k=5k=0.5P(X \geq 3) = P(X = 3) + P(X = 4) = 3k + 2k = 5k = 0.5.

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