Multiple choice

The sum of 24 terms of the series $1, -3, 4, -6, 7, -9, 10, ...$ is

  1. 24

  2. -24

  3. 16

  4. -16
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The series is (1-3) + (4-6) + (7-9) + ... for 12 pairs. Each pair sums to -2. 12 * -2 = -24.

AI explanation

The series can be grouped into pairs like (1 minus 3), (4 minus 6), and (7 minus 9), where each pair sums to -2. For 24 terms, there are exactly 12 such pairs. Multiplying 12 by -2 gives a total sum of -24.

Keep practicing — related questions