Water flows into a container through Tap R and flows out of the container through Tap S. The capacity of a container is 50 litres. When only Tap R is turned on, the container is completely filled in 12 minutes. When only Tap S 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 50% of the container?
- How much water has flowed out through Tap S by the time the container is 45 filled with water? Express your answer in litres.
(a)
Tap R :
12 min → 1 container
1 min →
112 container
13 hour =
13 x 60 = 20 min
Tap S:
20 min → 1 container
1 min →
120 container
Tap R and Tap S:
1 min →
112 -
120 =
560 -
360 =
130 container
1 container →
301 = 30 min
50% container → 50% x 30 = 15 min
(b)
Time taken to fill
45 of the container
1 container → 30 min
45 container → 30 x
45 = 24 min
Volume that flows out per min
=
120 container
=
120 x 50
= 2.5 ℓ
Volume of water that flowed out through Tap S in 24 min
= 24 x 2.5
= 60 ℓ
Answer(s): (a) 15 min; (b) 60 ℓ