Question

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?
(b) What was the maximum forecast temperature during the week?
(c) What was the minimum actual temperature during the week?
(d) On which day did the actual temperature differ the most from the forecast temperature?

Answer 1

We have two graphs actual and forecast, In the graph $x-$axis represents days and $y-$axis represents the temperature

Scale :

On $x-$axis $4$ cm $=1$ day

On $y-$axis $2$ cm $=5^{0}C$

To find the temperature at particular day:

Trace the vertical line parallel to $y-$axis passing from the point on $x-$axis, find the point where this vertical line intersects the graph.

Now from that point trace a horizontal line parallel to $x-$axis, this line intersects the $y-$axis at required point.

To find the day at particular temperature:

Trace the horizontal line parallel to $x-$axis passing from the temperature point on $y-$axis, find the point where this horizontal line intersects the graph.

Now from that point trace a vertical line parallel to $y-$axis, this line intersects the $x-$axis at required point.

Now,

a) Forecast temperature and actual temperature are same where the graphs of both intersects which is Tuesday, Friday and Sunday

b) Follow step 1 to find temperature for graph forecast on days of week,

Mon $-{15}^{0}C$

Tue $-{20}^{0}C$

Wed $-{25}^{0}C$

Thu $-{22.5}^{0}C$

Fri $-{15}^{0}C$

Sat $-{30}^{0}C$

Sun $-{35}^{0}C$

So, maximum forecast temperature during the week is ${35}^{0}C$

c) Follow step 1 to find temperature for actual graph on days of week

Mon$-{17.5}^{0}C$

Tue $-{20}^{0}C$

Wed$-{30}^{0}C$

Thu $-{15}^{0}C$

Fri $-{15}^{0}C$

Sat $-{25}^{0}C$

Sun $-{35}^{0}C$

So, minimum actual temperature during the week is ${15}^{0}C$

d) Difference between actual and forecast temperatures during the week

Mon, $17.5-15={2.5}^{0}C$

Tue, $20-20=0^{0}C$

Wed, $30-25=5^{0}C$

Thu, $15-22.5=-{7.5}^{0}C$

Fri, $15-15=0^{0}C$

Sat, $25-30=-5^{0}C$

Sun, $35-35=0^{0}C$

So, actual temperature differ most from forecast temperature is ${7.5}^{0}C$ which is on Thursday.