Carcass wrote:
If x is equal to the sum of the even integers from m to n, inclusive, where m and n are positive even integers, which of the following represents the value of x in terms of m and n?
A. \((\frac{m+n}{2})(\frac{n-m}{2} + 1)\)
B. \(3(m+n)\)
C. \(\frac{n^2 - m^2}{2}\)
D. \(6(m+n)\)
E. \((\frac{m+n}{2})(\frac{n-m}{2})\)
This is how I did...
since x is sum of m to n inclusive where m and n are even.
Let take such series => case 1: 2, 4 and 6 (or ) case 2: 2, 4, 6 and 8
Sub since m is starting and n is ending of the series.
case 1: x sum is = 12
m = 2 and n = 6 , sub in the options we get A as 12.
case 2: x sum is 20
m = 2 and n = 8 , sub in the options we get A as 20
Hence A.