Variance is the difference of the number from the mean of the group of numbers then square it and find the average. In this case, we need to find the mean first. 90 + 75 + 72 + 88 + 85 = 410/5 = 82 . Now we must get the difference of each from the mean.
90 - 82 = 8
75 - 82 = -7
72 - 82 = -10
88 - 82 = 6
85 - 82 = 3
Next is to find the average of the square of the numbers.
(8^2) + (-7^2) + (-10^2) + (6^2) + (3^2) is
64 + 49 + 100 + 36 + 6 = 255. Next step is to simply divide it by 5. The numerator in calculating the variance is the sum of the square of the numbers which is 255.
Oh my god I’m sorry for answering ur question but please don’t be exam or test , brainly will delete ur question because apparently it’s violating the terms of service , but much love I hope u pass <3
12 inch bucket fills half an inch every 10 mins
20 mins is 1 inch
40 mins is 2 inch
60 mins is 3 inch
80 mins is 4 inch
100 mins is 5 inch
120 mins is 60 inch and 6 inch is half of 12 so
double 120 to get 240 which is 4 hours
2 classes of 21 students each
21 × 2 classes = 42 students in total
42 × 3 mins = 126 minutes for 42 students
10 mins for 2 class pics = 20 minutes
126 + 20 = 146 minutes = 2 hours and 26 minutes
It should take 146 minutes (2 hours and 26 minutes) to take all the pictures.
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