PSLE
The graph shows the temperature of water in a pot from 2000 to 20 36.
- For how many minutes was the temperature of the water 50°C and below? Give your answer in min.
- During which two 6-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 2030 to 2036? Give your answer in °C/min.
(a)
Temperature of water that reached 50°C at 20 12.
From 20 12 to 20 36: 24 min
Duration that the temperature of water that reached 50°C and below = 24 min
(b)
Decrease in temperature of water
From 20 00 to 20 06: 76°C - 57°C = 19°C
From 20 6 to 20 12: 57°C - 50°C = 7°C
From 20 12 to 20 18: 50°C - 39°C = 11°C
From 20 18 to 20 24: 39°C - 30°C =
9°C
From 20 24 to 20 30: 30°C - 15°C = 15°C
From 20 30 to 20 36: 15°C - 6°C =
9°C
Two 6-minute intervals that the temperature of water decreas
es at the same rate are 20 18 to 20 24 and 20 30 to 20 24. (c)
Change in temperature per minute from 20 30 to 20 36
= 3 ÷ 6
= 0.5°C/min
Answer(s): (a) 24 min; (b) 20 18 to 20 24, 20 18 to 20 24; (c) 0.5°C/min