Problem P. 4128. (January 2009)
P. 4128. The pressure of the water supply of a city is maintained by a 24m high water column. What is the daily electrical energy consumption of a city which has 50 000 citizens if the average water consumption of a citizen is 100 litres per day, the efficiency of the pumps is 80%, and the efficiency of the electric motors is 92%?
What is the average electrical power input of the water plant?
(4 pont)
Deadline expired on 11 February 2009.
Statistics:
143 students sent a solution.  
4 points:  115 students. 
3 points:  10 students. 
2 points:  2 students. 
1 point:  8 students. 
Unfair, not evaluated:  8 solutions. 
