Q Two pipes a and b separately fill in 15 2 min and 5 min respactively and third pipe c

in 60 min. pipe a will fill the tank 8 times and pipe b 12 times.so in 1 hr the tank will be filled 8+12+1(already full at beginning)=21 times. so if capacity is X, 21X=14.60 , or X=40 capacity of tank
10 years agoHelpfull: Yes(16) No(2)
let capacity of cistern = x
a's speed= 2x/15 litre/min
b's speed= x/5 litre/min

a and b can fill in a minute= x[2/15 + 1/5]
= x/3 litre/min

but c can empty the full tank at the rate of 14 l/m
tank emptied in one minute= (x/3)-14= (x-14)/3 l/m

according to question
tank emptied in 1hr= 60 min
so,
(x-14)/3=1/60
x= 281/20
10 years agoHelpfull: Yes(7) No(4)
x+(x/5+2x/15)*60=60*14-I cant understand this step. please give me some more detailed explanation to this
10 years agoHelpfull: Yes(5) No(0)
Thank You Mohan Lal Garg
10 years agoHelpfull: Yes(1) No(1)
A fill cistern in one minute =1/15/2=2/15
B fill cistern in one minute =1/5
formula is -
work done by inlet pipe in 1min -work done by outlet pipe in 1 minute =(-1/60){because cistern emptied in one hour so in 1 min }
1/15/2+1/5 - (work done by outlet in 1minute = - 1/60
work done by outlet in 1 min = 2/15+1/5+1/60 =7/20
capacity of cistern= Flow rate in one min by waste pipe /work done by waste pipe in 1 min
=14/7/20=40 liters
2 years agoHelpfull: Yes(0) No(0)

Q. Two pipes a and b separately fill in 15/2 min and 5 min respactively and third pipe c can empty of 14l/m if all the pipes are open when the cistern is full, it is emptied in 1 hr. how many litres does the cistern hold?