(Q14).Find the sum of the following APs:

(iii) 0.6, 1.7, 2.8,…, to 100 terms.

Given A.P : 0.6, 1.7, 2.8,…. S100

a = ; d = a2 – a1 = = ; n =

Sn =
n
2
[2a + (n-1)d]
∴ S100 =
2
[2 × + (-1)]

= [ + × ]

= [ + ]

= ×

=