JAMB - Mathematics (1998 - No. 31)
If m and n are the mean and median respectively of the set of numbers 2, 3, 9, 7, 6, 7, 8, 5, find m + 2n to the nearest whole number
19
18
13
12
Explanation
mean(x) = \(\frac{\sum x}{N}\)
= \(\frac{48}{8}\)
= 5.875
re-arranging the numbers;
2, 3, 5, 6, 2, 7, 8, 9
median = \(\frac{6 + 7}{2}\)
= \(\frac{1}{2}\)
= 6.5
m + 2n = 5.875 + (6.5)2
= 13 + 5.875
= 18.875
= \(\approx\) = 19
= \(\frac{48}{8}\)
= 5.875
re-arranging the numbers;
2, 3, 5, 6, 2, 7, 8, 9
median = \(\frac{6 + 7}{2}\)
= \(\frac{1}{2}\)
= 6.5
m + 2n = 5.875 + (6.5)2
= 13 + 5.875
= 18.875
= \(\approx\) = 19
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