For all even integers n, h(n) is defined to be the sum of the even integers between 4 and n, inclusive. What is the value of h(18)/h(10) ?  Choose the correct choice from the following choices.
A) 3
B) 1.8
C) 6
D) 18
E) 60

Rationale: concept : when terms are in arithmetic progression ( a . p . ) i . e . terms are equally spaced then mean = median = ( first + last ) / 2 and sum = mean * number of terms h ( 18 ) = [ ( 4 + 18 ) / 2 ] * 8 = 88 h ( 10 ) = ( 4 + 10 ) / 2 ] * 4 = 28 h ( 18 ) / h ( 10 ) = ( 88 ) / ( 28 ) ~ 3 answer : a
Answer: A