## Thursday, September 9, 2010

### Volume P6 2010 SA2 Red Swastika P2 Q13

Shanna placed three empty tanks side by side as shown below. The smallest tank has a crack at the bottom of its side and the base area of each tank is 16 cm3. After she turned on the tap for 64 minutes, the height of the water in the smallest tank became 6 cm although 0.7 ml of water is leaking out of the crack per minute. Find the rate of flow of water from the tap. Give your answer in ml/min.

20 + 12 + 6 = 38

38 x 16 = 608

608/64 = 9.5

9.5 + 0.7 = 10.2 ml/min

It was 10.2 ml/min.

1. Isn't the student assuming that the tank has been leaking for all the 64 minutes that it was turned on?

2. The tank should not be leaking for the entire 64 minutes as the last tank would have been empty while the first 2 tanks were filling up with water.

3. Are you sure the answer is correct? I got 5.2ml/min

4. 0.7 ml per minute leaked out. So it is already the rate given, hence there is no need to know how long it has been leaking.