Question

find the sum of integers which are multiples of 6 and lie between 200 and 500​

Answer 1

a=204

d=6

l=498

n=?

l=a+(n-1) d

498=204+(n-1) 6

498-204=n-1

6

294=n-1

6

49+1=n

50=n

sum=n (a+l)

2

=50(204+498)

2

=25 x 702

=17550