Math, asked by 9423476133, 1 year ago

the sum of all natural numbers between 200 and 400 which are divisible by 7

Attachments:

Answers

Answered by shimy
7
203 + 210 ...... + 399
a= 203. tn = 399 d= 7
tn = a+(n-1)d
399= 203+(n-1)7
n=29

s29 = 29/2 [ 2(203) + (29-1)(7) ]
s29 = 8729
Similar questions