PSLE
The graph shows the temperature of water in a pot from 1300 to 13 48.
- For how many minutes was the temperature of the water 60°C and below? Give your answer in min.
- During which two 8-minute intervals did the temperature of water decrease at the same rate? Give your answer in the following format. (Eg 01 00 to 01 15, 01 25 to 01 30)
- What was the change in temperature per minute from 1332 to 1340? Give your answer in °C/min.
(a)
Temperature of water that reached 45°C at 13 16.
From 13 08 to 13 48: 40 min
Duration that the temperature of water that reached 60°C and below = 40 min
(b)
Decrease in temperature of water
From 13 00 to 13 08: 67°C - 60°C = 7°C
From 13 8 to 13 16: 60°C - 45°C = 15°C
From 13 16 to 13 24: 45°C - 33°C = 12°C
From 13 24 to 13 32: 33°C - 24°C = 9°C
From 13 32 to 13 40: 24°C - 18°C =
6°C
From 13 40 to 13 48: 18°C - 12°C =
6°C
Two 8-minute intervals that the temperature of water decreas
es at the same rate are 13 24 to 13 32 and 13 32 to 13 40. (c)
Change in temperature per minute from 13 32 to 13 40
= 6 ÷ 8
= 0.75°C/min
Answer(s): (a) 40 min; (b) 13 24 to 13 32, 13 32 to 13 40; (c) 0.75°C/min