Find the sum :

0.6 + 1.7 + 2.8 +….. to 100 terms.

We know that,

Sum of n terms of an A.P. is given by,

∴ S_n = $\dfrac{n}{2}$ [2a + (n - 1)d]

Given,

a = 0.6

d = 1.7 - 0.6 = 1.1

n = 100

⇒ S₁₀₀ = $\dfrac{100}{2}$ [2(0.6) + (100 - 1)1.1]

= 50 [1.2 + (99)1.1]

= 50 [1.2 + 108.9]

= 50 (110.1)

= 5505.

Hence, S₁₀₀ = 5505.