A group of students were surveyed on the number of hours they spend on the internet in a week. The table below shows the results.

Hours using the internet |
Fewer than 15 h |
16 h |
17 h |
18 h |
19 h |
20 h |

Number of students |
0 |
68 |
71 |
45 |
30 |
40 |

(a) How many students took part in
the survey?

(b) How many hours per week were
spent on the internet by all of the students that participated?

(C) What was the average time spent
on the internet per student? Round your answer to the nearest whole number