Question

3)Two taps can fill a cistern in 12 hours and 15 hours respectively. A third tap can empty it in 10 hours. How long

will they take to fill the cistern, if all of them are opened together?​
plzz send the working

Answer 1

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first tap can fill a cistern in 12 hours

first tap can fill 1/12 part In 1 hours

second tap can fill a cistern in 15 hours

second tap can fill 1/15 part In 1 hours

third tap can fill a cistern in 10 hours

third tap can fill 1/10 part in 1 hours

their combine work in 1 hours=1/12+1/15+1/10

=5+4+6/60

=15/60

=1/4

they fill together 1/4 part In 1 hours

they fill together full part In 1÷1/4hours

=4 hours

time and work in mathematics

To calculate work done in a given time in general if a person A completes a piece of work in a 'n' days, then A's one day work = 1/n. If a man takes 10 days to complete a piece of work, then according to the unitary method work done in one day = 1/10.