PSLE
The graph shows the temperature of water in a pot from 2200 to 22 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 2228 to 2235? Give your answer in °C/min.
(a)
Temperature of water that reached 55°C at 22 14.
From 22 07 to 22 42: 35 min
Duration that the temperature of water that reached 60°C and below = 35 min
(b)
Decrease in temperature of water
From 22 00 to 22 07: 79°C - 60°C = 19°C
From 22 7 to 22 14: 60°C - 55°C = 5°C
From 22 14 to 22 21: 55°C - 37°C = 18°C
From 22 21 to 22 28: 37°C - 21°C = 16°C
From 22 28 to 22 35: 21°C - 14°C =
7°C
From 22 35 to 22 42: 14°C - 7°C =
7°C
Two 7-minute intervals that the temperature of water decreas
es at the same rate are 22 21 to 22 28 and 22 28 to 22 35. (c)
Change in temperature per minute from 22 28 to 22 35
= 7 ÷ 7
= 1°C/min
Answer(s): (a) 35 min; (b) 22 21 to 22 28, 22 28 to 22 35; (c) 1°C/min