The distance (in km) of 40 engineers from their residence to their place of work were found

The distance (in km) of 40 engineers from their residence to their place of work were found as follows
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What is the empirical probability that an engineer lives
(i) less than 7 km from her place of work?
(ii) more than or equal to 7 km from her place of work?
(iii) within \frac { 1 }{ 2 } km from her place of work?