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Class 8 - (Math )
Operations on numbers - Average
The average temperature of the first four days of a week was 40.2 °C and the average temperature of the last four days was 41.3 °C. If the average temperature for a full week is 40.6°C, what is the temperature on the fourth day?
a :
40.8 degrees
b :
42.8 degrees
c :
39.8 degrees
d :
41.8 degrees
Explanation :
Sum of days 1 to 4: 4 x 40.2 = 160.8
Sum of days 4 to 7: 4 x 41.3 = 165.2
Total week sum: 7 x 40.6 = 284.2
Fourth day temperature: (160.8 + 165.2) - 284.2 = 326 - 284.2 = 41.8
Sum of days 4 to 7: 4 x 41.3 = 165.2
Total week sum: 7 x 40.6 = 284.2
Fourth day temperature: (160.8 + 165.2) - 284.2 = 326 - 284.2 = 41.8