What is the sum of the odd integers from 35 to 85, inclusive?
1,560
1,500
1,240
1,120
1,100
题目分析：
35 到 85 的奇数，构成一个等差数列，方差是 2. 奇数的个数为(85-35)/2+1=26.
等差数列的和 S=n*(a(1)+a(n))/2= ~$\frac{26*(35+85)}{2}$~ =1560;
综上：答案就是 A。
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consecutive integers FirstNumber+LastNumber2FirstNumber+LastNumber2 divided by2 as we need to find out the number of odd numbers.(85-35)+1 is total number which includes even and odd
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consecutive integers
FirstNumber+LastNumber2FirstNumber+LastNumber2
divided by2 as we need to find out the number of odd numbers.(85-35)+1 is total number which includes even and odd
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