Water flows into a tank through Tap S and flows out of the container through Tap T. The capacity of a tank is 66 litres. When only Tap S is turned on, the container is completely filled in 12 minutes. When only Tap T 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 90% of the tank?
- How much water has flowed out through Tap T by the time the tank is 25 filled with water? Express your answer in litres.
(a)
Tap S :
12 min → 1 tank
1 min →
112 tank
14 hour =
14 x 60 = 15 min
Tap T:
15 min → 1 tank
1 min →
115 tank
Tap S and Tap T:
1 min →
112 -
115 =
560 -
460 =
160 tank
1 tank →
601 = 60 min
90% tank → 90% x 60 = 54 min
(b)
Time taken to fill
25 of the tank
1 tank → 60 min
25 tank → 60 x
25 = 24 min
Volume that flows out per min
=
115 tank
=
115 x 66
= 4.4 ℓ
Volume of water that flowed out through Tap T in 24 min
= 24 x 4.4
= 105.6 ℓ
Answer(s): (a) 54 min; (b) 105.6 ℓ