Answers

2015-07-16T21:31:55+08:00
The answer here is 153

first, use an=a1+d(n-1) with a1= 9, and an=25,
take note that we need odd numbers, therefore, d=2, since there is 2 common difference between 2 odd numbers (i.e. 3, 5 <-- 5-3=2)

solve for n, you have 9

then use
sn=[n(a1+an)] / 2 with n=9, a1= 9, an=25

solv it, youll get 153
0