Answer:
39
Step-by-step explanation:
4 x 1 x 3 + 3 x 1 x 2 + 7 x 3
4 x 3 + 3 x 1 x 2 + 7 x 3
12 + 3 x 1 x 2 + 7 x 3
12 + 3 x 2 + 7 x 3
12 + 6 + 7 x 3
12 + 6 + 21
39
Step-by-step explanation:
The mean is 27 and the standard deviation is 4.
23 is 1 standard deviation below the mean, and 31 is 1 standard deviation above the mean. According to the empirical rule, 68% of the population is between -1 and +1 standard deviations.
68% of 1200 is 816.
19 is 2 standard deviations below the mean, and 35 is 2 standard deviations above the mean. According to the empirical rule, 95% of the population is between -2 and +2 standard deviations.
95% of 1200 is 1140.
You haven't shared the list of expressions from which you are to choose an answer.
However: you can perform this estimation yourself as follows:
Round off both -21.87 and 4.79. -21.87 goes to -22 and 4.79 to 5. Then
a good estimate of -21.87 divided by 4.79 would be -22/5, or -4.4.
