Water flows into a tank through Tap V and flows out of the container through Tap W. The capacity of a tank is 72 litres. When only Tap V is turned on, the container is completely filled in 14 minutes. When only Tap W is turned on, it takes
14 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 74% of the tank?
- How much water has flowed out through Tap W by the time the tank is 25 filled with water? Express your answer in litres.
(a)
Tap V :
14 min → 1 tank
1 min →
114 tank
14 hour =
14 x 60 = 15 min
Tap W:
15 min → 1 tank
1 min →
115 tank
Tap V and Tap W:
1 min →
114 -
115 =
15210 -
14210 =
1210 tank
1 tank →
2101 = 210 min
74% tank → 74% x 210 = 155.4 min
(b)
Time taken to fill
25 of the tank
1 tank → 210 min
25 tank → 210 x
25 = 84 min
Volume that flows out per min
=
115 tank
=
115 x 72
= 4.8 ℓ
Volume of water that flowed out through Tap W in 84 min
= 84 x 4.8
= 403.2 ℓ
Answer(s): (a) 155.4 min; (b) 403.2 ℓ