A swimming pool is left to heat up over a weekend. Unfortunately, the thermostat does not work properly and the pool overheats. The temperature of the water at 09:00 on Monday morning is 56 °C.
The heater is switched off and temperature readings are taken every 6 hours over the next three days. The results are shown below.

a. Plot a line graph of the data and draw a smooth curve through the points.
b. Estimate the temperature of the pool at 18:00 on Monday evening.

c. The pool can only be opened to the public once the temperature has dropped to 25 °C.
Estimate the time at which the pool could have been opened.
d. At what time was the temperature of the pool dropping the fastest? Explain, with reference to your graph, how you reached your answer.

Transcribed Image Text:

Day Time Temperature (°C) 56 40 32 Monday 09:00 15:00 21:00 03:00 09:00 15:00 21:00 03:00 09:00 15:00 21:00 Tuesday 27 Wednesday 23 21 20 19.5 19 18.5 18