Consider the sequence of numbers beginning 23, 27, 28, 32, 33... It continues in such a way that by adding 5 to the nth term, one obtains the (n + 2)th term. What is the sum of the first 15 members of this sequence?
Select the correct option.
A) 618  B) 900  C) 788  D) 928  E) 1022
I would split them up like this.   23 28 33 and so on (8 terms)....the 8th term = 23+7*5= 
<gadget id="calculator">23+7*5</gadget>
<output>58</output>
58   27 32 37 and so on (7 terms)......the 7th term= 27+6*5= 
<gadget id="calculator">27+6*5</gadget>
<output>57</output>
57   Since the distance between any two numbers is the same we can use arithmetics   first+last/2 times no of numbers= the sum   (23+58)/2 * 8= 
<gadget id="calculator">(23+58)/2 * 8</gadget>
<output>324</output>
324   (27+57)/2 * 7= 
<gadget id="calculator">(27+57)/2 * 7</gadget>
<output>294</output>
294= 618   618
<result>A</result>
Consider the sequence of numbers beginning 23, 27, 28, 32, 33... It continues in such a way that by adding 5 to the nth term, one obtains the (n + 2)th term. What is the sum of the first 15 members of this sequence?