Water flows into a tank through Tap D and flows out of the container through Tap E. The capacity of a tank is 60 litres. When only Tap D is turned on, the container is completely filled in 16 minutes. When only Tap E 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 78% of the tank?
- How much water has flowed out through Tap E by the time the tank is 45 filled with water? Express your answer in litres.
(a)
Tap D :
16 min → 1 tank
1 min →
116 tank
13 hour =
13 x 60 = 20 min
Tap E:
20 min → 1 tank
1 min →
120 tank
Tap D and Tap E:
1 min →
116 -
120 =
580 -
480 =
180 tank
1 tank →
801 = 80 min
78% tank → 78% x 80 = 62.4 min
(b)
Time taken to fill
45 of the tank
1 tank → 80 min
45 tank → 80 x
45 = 64 min
Volume that flows out per min
=
120 tank
=
120 x 60
= 3 ℓ
Volume of water that flowed out through Tap E in 64 min
= 64 x 3
= 192 ℓ
Answer(s): (a) 62.4 min; (b) 192 ℓ