(a) Solve the simultaneous equation : \(\log_{10} x + \log_{10} y = 4\)
                              \(\log_{10} x + 2\log_{10} y = 3\)~(b) The time, t,taken to buy fuel at a petrol station varies directly as the number of vehicles V on queue and jointly varies inversely as the number of pumps P available in the station. In a station with 5 pumps, it took 10 minutes to fuel 20 vehicles. Find :
(i) the relationship between t, P and V ; (ii) the time it will take to fuel 50 vehicles in the station with 2 pumps ; (iii) the number of pumps required to fuel 40 vehicles in 20 minutes.