Use the partial sum formula to find the partial sum of the given arithmetic sequence.
-Find the sum of the odd integers between 24 and 66.
A) 900
B) 990
C) 945
D) 1035

Question

Quizplus · Accepted Answer

The odd integers between 24 and 66 are 25, 27, ..., 65. This is an arithmetic sequence with the first term a = 25, the last term l = 65, and the common difference d = 2. The number of terms n can be found using the formula n = (l - a)/d + 1 = (65 - 25)/2 + 1 = 21. The partial sum S_n of an arithmetic sequence is given by S_n = n/2 * (a + l). Substituting the values, S_21 = 21/2 * (25 + 65) = 21/2 * 90 = 945.

Use the Partial Sum Formula to Find the Partial Sum