Q1 of 178 Page 551

Find the sum of each of the following APs:
0.6, 1.7, 2.8, ... to 100 terms.

Here, first term = 0.6

Common difference = 1.7 - 0.6 = 1.1

Sum of first n terms of an AP is

S_n = [2a + (n - 1)d]

∴ S₁₀₀ = [2(0.6) + (100 - 1)(1.1)]

= (50) × [1.2 + (99 × 1.1) ]

= 50 × [1.2 + 108.9]

= 50 × 110.1

= 5505

Thus, sum of 100 terms of this AP is 5505.

Find the sum of each of the following APs:

– 37, – 33, – 29, ... to 12 terms.

Find the sum of each of the following APs:

(1/15), (1/12), (1/10),…….. to 11 terms.

Find the sum of each of the following arithmetic series:

34 + 32 + 30 + … + 10.

Find the sum of each of the following APs:0.6, 1.7, 2.8, ... to 100 terms.