Question

Find the sum 0.6 + 1.7 + 2.8 + .................... to 100 terms.

Answer 1

Here, $$a = 0.6, \ d = 1.1, \ n = 100$$.

$$S_{100} = \frac{100}{2}[2(0.6) + 99(1.1)]$$

$$= 50(1.2 + 108.9)$$

$$= 50(110.1)$$

$$= 5505$$