A pipe can fill a tank in 'x' hours and another pipe can empty it in'y' (y > x) hours. If both the pipes are open , in how many hours will the tank be filled ?
1). (x-y) hours
2). (y-x) hours
3). $\frac{xy}{x-y}$ hours
4). $\frac{xy}{y-x}$ hours
A tap can empty a tank in 30 minutes. A second tap can empty it in 45 minutes. If both the taps operate simultaneously, how much time is needed to empty the tank
1). 30 minutes
2). 18 minutes
3). 14 minutes
4). 15 minutes
Having the same capacity 9 taps fill up a water tank in 20 minutes. How many taps of the same capacity are required to fill up the same water tank in 15 minutes
1). 10
2). 12
3). 15
4). 18
A tap drips at a rate of one drop/ sec, 600 drops make 100ml. The number of litres wasted in 300 days is
1). 432000
2). 432000
3). 43200
4). 4320
Which of these pipes will empty a pool the fastest (i) One pipe of diameter 60 cm (ii) Two pipes of diameter 30 cm each (iii) three pipes of diameter 20 cm each
1). (i)
2). (iii)
3). (ii)
4). None of these