**Question:**

Draw the temperature-time graph in each of the following cases:

(i)

Time (in hours): |
7:00 | 9:00 | 11:00 | 13:00 | 15:00 | 17:00 | 19:00 | 21:00 |

Temperature (°F) in: |
100 | 101 | 104 | 102 | 100 | 99 | 100 | 98 |

(ii)

**Solution:**

Here, time is an independent variable and temperature is a dependent variable. So, we take time on the x-axis and temperature on the y-axis.

Let us choose the following scale:

For point (i):

On x-axis: 1 cm = 1 hours

On y-axis: 1 cm = 2οF

For point (ii):

On x-axis: 2 cm = 2 hours

On y-axis: 1 cm = 1οF

Let us assume that on the x-axis, the coordinate of origin is 6:00.

On y-axis, the coordinate of origin is 94οF .

So, the coordinates of O are (6:00, 94).

Now, let us plot (7:00, 100), (9:00, 101), (11:00, 104),..(21:00, 98) for point (i) and (8:00, 100), (10:00, 101), (12:00, 104),...,(20:00, 100) for point (ii). These points are joined to get the graphs representing the given information as shown in the figures below.

(i)

(ii)