Water flows into a container through Tap Z and flows out of the container through Tap A. The capacity of a container is 80 litres. When only Tap Z is turned on, the container is completely filled in 16 minutes. When only Tap A is turned on, it takes
13 hour for all the water to flow out. If both taps are turned on at the same time,
- How long does it take to fill 46% of the container?
- How much water has flowed out through Tap A by the time the container is 45 filled with water? Express your answer in litres.
(a)
Tap Z :
16 min → 1 container
1 min →
116 container
13 hour =
13 x 60 = 20 min
Tap A:
20 min → 1 container
1 min →
120 container
Tap Z and Tap A:
1 min →
116 -
120 =
580 -
480 =
180 container
1 container →
801 = 80 min
46% container → 46% x 80 = 36.8 min
(b)
Time taken to fill
45 of the container
1 container → 80 min
45 container → 80 x
45 = 64 min
Volume that flows out per min
=
120 container
=
120 x 80
= 4 ℓ
Volume of water that flowed out through Tap A in 64 min
= 64 x 4
= 256 ℓ
Answer(s): (a) 36.8 min; (b) 256 ℓ