amorphous wrote:
If the average (arithmetic mean) of seven consecutive integers is k + 2, then the product of the greatest and least integer is ?
A. k2 – 9
B. k2 – 2k + 1
C. k2 + 4k – 12
D. k2 + 6k + 9
E. k2 + 4k – 5
Here
we know k + 2 is the Arithmetic Mean and there are 7 nos
SO the numbers are; K - 1, K , K + 2 , K + 3, K + 4, K + 5
i.e. arithmetic mean =
(K−1)+(K)+(K+2)+(K+3)+(K+4)+K+5)7= k + 2
So the greatest number = k + 5 and the smallest number = K - 1
So the product =(k + 5) * (k - 1) =
k2 + 4k – 5