tmua.me Medium Set B Paper 1 · Question 17

A histogram represents journey times $t$ , in minutes. Its classes and frequency densities are shown below, where $k>0$ .

\begin{array}{c|ccc} \text{Journey time} & 0\leq t<10 & 10\leq t<30 & 30\leq t<40\\[3pt] \hline \text{Frequency density} & 2 & k & 3 \end{array}

The estimate of the mean calculated using the class midpoints is $22$ minutes.

What is the estimated median, in minutes, obtained by linear interpolation at half the total frequency?

17

20

22

24

40

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