Question

Question 1 (i)
Find the sum of the following APs.
(i) 2, 7, 12,…., to 10 terms

Answer 1

(i) $2,7,12,\dots \dots ,to10termsForthisA.P.,a=2d=a_2-a_1=7-2=5n=10Weknowthat,S_n=\frac{n}{2}[2a+(n-1\left)d\right]S_{10}=\frac{10}{2}\left[2\right(2)+(10-1)\times 5]=5[4+(9)\times (5\left)\right]=5\times 49=245$