Question

23rd term of an arithmetic sequence is 32. 35^th term is 104. Then

a. What is the common difference?

b. Which is the middle term of first 35 terms of this sequence?

c. Find the sum of first 35 terms of this sequence.

Answer 1

a. 23rd term = 32

35th term = 104

x₂₃ + 12d = x₃₅

12d = 104 - 32 = 72

d = 6

b. Middle term offirst 35 terms = \(\sqrt{4}\)

c. 18 th term = X₁₉ = X₂₃ – 5d = 32 -5 × 6 = 32 – 30 = 2

Sum of 35 terms = 18^th term × 35 = 70