PSLE
The graph shows the temperature of water in a pot from 1100 to 11 36.
- For how many minutes was the temperature of the water 60°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 1130 to 1136? Give your answer in °C/min.
(a)
Temperature of water that reached 60°C at 11 12.
From 11 12 to 11 36: 24 min
Duration that the temperature of water that reached 60°C and below = 24 min
(b)
Decrease in temperature of water
From 11 00 to 11 06: 79°C - 72°C = 7°C
From 11 6 to 11 12: 72°C - 60°C = 12°C
From 11 12 to 11 18: 60°C - 43°C = 17°C
From 11 18 to 11 24: 43°C - 37°C =
6°C
From 11 24 to 11 30: 37°C - 21°C = 16°C
From 11 30 to 11 36: 21°C - 15°C =
6°C
Two 6-minute intervals that the temperature of water decreas
es at the same rate are 11 18 to 11 24 and 11 30 to 11 24. (c)
Change in temperature per minute from 11 30 to 11 36
= 6 ÷ 6
= 1°C/min
Answer(s): (a) 24 min; (b) 11 18 to 11 24, 11 18 to 11 24; (c) 1°C/min