Answer:
-1°C
Step-by-step explanation:
[tex]Mean = \frac{\text{Sum of all observations}}{\text{No. of observations}}[/tex]
Now we are given the mean temperature for the first 4 days in January was 9°C
So, [tex]9 = \frac{\text{Sum of temperatures of first 4 days}}{4}[/tex]
[tex]9 \times 4 = \text{Sum of temperatures of first 4 days}[/tex]
[tex]36= \text{Sum of temperatures of first 4 days}[/tex]
Now we are given that the mean temperature for the first 5 days in January was 7°C
[tex]7 = \frac{\text{Sum of temperatures of first 5 days}}{5}[/tex]
[tex]7 \times 5 = \text{Sum of temperatures of first 5 days}[/tex]
[tex]35= \text{Sum of temperatures of first 5 days}[/tex]
So, Temperature on 5th day = Sum of temperatures of first 5 days -Sum of temperatures of first 4 days
Temperature on 5th day = 35°C-36°C = -1°C
Hence the temperature on the 5th day was -1°C
