The following graph shows the temperature forecast and the actual temperature for each day of a week. (a) On which day was the forecast temperature the same as the actual temperature?

We have two graphs: actual and forecast. In the graph, the x-axis represents days and the y-axis represents the temperature. Scale: On x-axis 4cm=1 day, On y-axis 2cm=50C

To find the temperature at a particular day:
Trace the vertical line parallel to the y-axis passing from the point on the x-axis, find the point where this vertical line intersects the graph. Now from that point, trace a horizontal line parallel to the x-axis; this line intersects the y-axis at the required point.

To find the day at a particular temperature:
Trace the horizontal line parallel to the x-axis passing from the temperature point on the y-axis, find the point where this horizontal line intersects the graph. Now from that point, trace a vertical line parallel to the y-axis; this line intersects the x-axis at the required point.

Now,
a) Forecast temperature and actual temperature are the same where the graphs of both intersect, which is Tuesday, Friday, and Sunday.
b) Follow step 1 to find the temperature for the forecast graph on days of the week:
Mon: °C
Tue: 20°C
Wed: 25°C
Thu: 2.50°C
Fri: °C
Sat: °C
Sun: °C
So, the maximum forecast temperature during the week is 35°C.
c) Follow step 1 to find the temperature for the actual graph on days of the week:
Mon: 19.50°C
Tue: 20°C
Wed: °C
Thu: °C
Fri: °C
Sat: 25°C
Sun: °C
So, the minimum actual temperature during the week is 15°C.
d) Difference between actual and forecast temperatures during the week:
Mon, 17.5 - 19.5 = -2.5°C
Tue, 20 - 20 = 0°C
Wed, 30 - 25 = 5°C
Thu, 15 - 2.5 = 12.5°C
Fri, 15 - 17.5 = -2.5°C
Sat, 25 - 22.5 = 2.5°C
Sun, 35 - 32.5 = 2.5°C
So, the actual temperature differs most from the forecast temperature by 12.5°C, which is on Thursday.