Question

Find the sum of the AP 1 + 3 ½/2 +6.... 101

Answer 1

2091

Explanation:

`1+3.5+6+\cdots+101 \\ \\ n=(101-1)/(2.5)+1=41 \\ \\ a=1 \\ \\ d=2.5 \\ \\ S=(41)/(2)[2(1)+(41-1)(2.5)] \\ \\ =2091`