Question

The height of each student in a class was measured and it was found that the mean height was 160cm.
Two students were absent. When their heights were included in the data for the class, the mean height
did not change. Which of the following heights are possible for the two absent students?
(A) 155 cm and 162 cm
(B) 152 cm and 167 cm
(C) 149 cm and 171 cm
(D) 143 cm and 178 cm

Answer 1

if the mean height didnt change then the mean of their heights is also 160cm

Answer 2

@danijava Which of the options averages to 160?

You can get the average of each pair of options and look for a pair that averages to 160.

Consider, 155 cm and 162 cm.

155 + 162 = 317 which when divided by 2 is not equal to 160.

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Or, you can look and if each pair member is balanced about the mean of 160.

Consider, 155 cm and 162 cm.

155 is 5 below 160 and 162 is only 2 above 160 so that is not the correct answer pair.

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Which pair do you think it is? Post what you get and we can compare answers, okay?