The graph below shows the amount of water in the tank over 16 minutes.

(a) What fraction of the tank was filled 4 minutes after Tap A was turned on? Express your answer in the simplest form.

(b) In one minute, how many litres of water flowed from Tap B?

5/35 = 1/7

a) 1/7 of the tank was filled 4 minutes after Tap A was turned on.

35 - 5 = 30

10 - 4 = 6

30/6 = 5

5/4 = 1.25

5 - 1.25 = 3.75 litres

Alternative method

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10 - 4 = 6

6/4 x 5 = 7.5

35 - 5 - 7.5 = 22.5

22.5/6 = 3.75 litres

b) In one minutes, 3.75 litres of water flowed from Tap B.

As appeared in PSLE 2010 exam:

ReplyDeleteChris filled a tank with water using two taps. He turned on Tap A first and after 4 minutes, he also turned on Tap B. Both taps were turned off at the same time when the tank was completely filled without overflowing.

The graph below shows the amount of water in the tank over 16 minutes.

Graph as shown:

Y-axis: Volume in lites, scale labelled from 0 to 40 and each interval was 5 litres.

X-axis: Time in minutes, scale labelled from 0 to 16 min and each interval was 2 minutes.

Note: X-axis, Y-axis

Start at 0.0

Next at 4,5

Next at 10, 35

Final at 16, 35

(a) What fraction of the tank was filled 4 minutes after Tap A was turned on? Express your answer in the simplest form.

(b) In one minute, how many litres of water flowed from Tap B?

Need some help...

ReplyDeleteThree balls are thrown at random into five bowls so that each ball has the same chance of going into any bowl independently of wherever the other 2 balls fall. Determine the probability distribution of the number of empty bowls.

Answer: 0.48 or 12 / 25