Question

Find the sum of
1-6 + 2-7 +3-8 + .......... to 100 terms.
solve and I will mark u as brainlist​

Answer 1

Answer:

Correct option (a) –250.

Step-by-step explanation:

The series (1 – 6 + 2 – 7 + 3 – 8 +… to 100 terms) can be rewritten as: ⇒ (1 + 2 + 3 + … to 50 terms) – (6 + 7 + 8 + … to 50 terms) Both these are AP’s with values of a and d as → a = 1, n = 50 and d = 1 and a = 6, n = 50 and d = 1, respectively. Using the formula for sum of an A.P. we get: → 25(2 + 49) – 25(12 + 49) → 25(51 – 61) = –250