Question

Category 3, 7, 11, 15. . . . . . . Find the sum up to the 40th term of

(a) 3442 (b) 3443

(c) 3242 (d)3240​

Answer 1

Answer:

an=a+(n-1)d

an=3+(40-1)4

an=3+156

an=159

Sn=n/2(a+l)

S40= 40/2(3+159)

=20(162)

= 3240

Ans: 3240