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
Sn = [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.