The frequency table shows how many visits to the library students in a school have made in the last month. Visits Frequency
0 171
1 368
2 224
3 10
4 211
5 298

Work out the mean.
Give your answer rounded to 1 DP.

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min