# Video: AQA GCSE Mathematics Higher Tier Pack 4 • Paper 3 • Question 15

The graph shows how the temperature changes over a particular day at a holiday resort in Spain. a) For how many hours of the day is the temperature above 26°C? b) What is the change in temperature between 02:00 and 14:00?

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### Video Transcript

The graph shows how the temperature changes over a particular day at a holiday resort in Spain. Part a) For how many hours of the day is the temperature above 26 degrees Celsius? Part b) What is the change in temperature between the time of the day 02:00 o’clock and 14:00?

We notice that the horizontal axis of the graph represents the time of day and the vertical axis represents the temperature measured in degrees Celsius. If we want to consider for how many hours of the day the temperature is above 26 degrees Celsius, we can mark the line 26 degrees Celsius.

The first intersection tells us when the temperature rose above 26 degrees Celsius. At this point, we need to consider the scale of the time of day. We have a label of 08:00 and 12:00. And in between those two labels are four spaces. From 08:00 to 12:00 represents a change in four hours. And that means each of our small boxes in this graph represents one hour. Our intersection is one small box past 08:00, and that means it’s 09:00 am.

We can also mark the point where the temperature begins to drop below 26 degrees, which is the time of 20:00. From 09:00 to 20:00 is 11 hours. The temperature was above 26 degrees Celsius for 11 hours.

Part b) wants to know what is the change in temperature between 02:00 and 14:00. We’ve already said that each of the little tiny boxes represents one hour. That means we need to go two spaces from zero, which would be the initial time of 02:00 o’clock. At 02:00 o’clock, the temperature was 14 degrees. The time 14:00 would be two small boxes from 12:00. And at 14:00, the temperature was 34 degrees. The change in temperature would be represented by the difference between 34 degrees and 14 degrees. 34 minus 14 equals 20. And that means, from 02:00 to 14:00, the temperature increased by 20 degrees Celsius.