PSLE
The graph shows the temperature of water in a pot from 1100 to 11 42.
- For how many minutes was the temperature of the water 60°C and below? Give your answer in min.
- During which two 7-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 1128 to 1135? Give your answer in °C/min.
(a)
Temperature of water that reached 40°C at 11 14.
From 11 07 to 11 42: 35 min
Duration that the temperature of water that reached 60°C and below = 35 min
(b)
Decrease in temperature of water
From 11 00 to 11 07: 73°C - 60°C = 13°C
From 11 7 to 11 14: 60°C - 40°C = 20°C
From 11 14 to 11 21: 40°C - 34°C = 6°C
From 11 21 to 11 28: 34°C - 24°C = 10°C
From 11 28 to 11 35: 24°C - 17°C =
7°C
From 11 35 to 11 42: 17°C - 10°C =
7°C
Two 7-minute intervals that the temperature of water decreas
es at the same rate are 11 21 to 11 28 and 11 28 to 11 35. (c)
Change in temperature per minute from 11 28 to 11 35
= 7 ÷ 7
= 1°C/min
Answer(s): (a) 35 min; (b) 11 21 to 11 28, 11 28 to 11 35; (c) 1°C/min