First we develop the combined recurrence table
Speed ( in km/h) Number of players Cumulative recurrence
85 – 100 11 11
100 – 115 9 11 + 9 = 20
115 – 130 8 20 + 8 = 28
130 – 145 5 28 + 5 = 33
It is given that, n = 33
\[\therefore n/2\text{ }=\text{ }33/2\text{ }=\text{ }16.5\]
Subsequently, the middle class is 100 – 115.
Where, lower limit(l) = 100
Recurrence (f) = 9
Total recurrence (cf) = 11
Furthermore, class width(h) = 15
\[=\text{ }100\text{ }+\text{ }82.5/9\]
\[=\text{ }100\text{ }+\text{ }9.17\]
= 109.17
Subsequently, the middle bowling speed is 109.17 km/h.