SOLUTION: Given twelve consecutive odd integers, the ninth of which is R + 4, find the sum of the third and the twelfth of these odd integers. (Translating Word Phrases into Mathematical

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: Given twelve consecutive odd integers, the ninth of which is R + 4, find the sum of the third and the twelfth of these odd integers. (Translating Word Phrases into Mathematical      Log On


   



Question 370570: Given twelve consecutive odd integers, the ninth of which is R + 4, find the sum of the third and the twelfth of these odd integers.
(Translating Word Phrases into Mathematical Expression)

Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
a9 = r + 4 = a1+ (9-1)2 = a1 + 16. Hence a1 = r - 12.
Thus a3 = r - 12 + 2*2 = r -12+4 = r - 8, and
a13 = r - 12 + 12*2 = r - 12 + 24 = r + 12. The sum of the 3rd and 13th terms is then r - 8 + r + 12 = 2r + 4.