waecE-LEARNING
Further Mathematics Paper 2, Nov/Dec. 2014  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Main
General Comments
Weakness/Remedies
Strength








Question 6

The deviations from the mean of a set of numbers are

-2, x, (x + 7), (x + 2)2 and (x + 3)2, where x is a constant.

Find the value of x.

 

 

 

 

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Observation

The Chief Examiner reported that this was also a very popular question among the candidates and they performed well in it. Majority of the candidates were reported to have recalled that for a given set of numbers, the sum of all the deviations from the mean = 0. i.e. -2 + x+7 (x+2)2 + (x+3)2 = 0. Expanding the squares and simplifying the equation gave x2 + 6x + 9 = 0 i.e. (x+3)2 = 0 Hence, x = -3.

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