Question

Find the sum of integers from 11 to 1000 which are divisible by 3

Answer 1

the numbers from 11 to 1000 which are divisible by 3 are
12,15,18,.....,999
this is an AP

of the AP
ist term = 12
common difference = 3
last term = 999
12+ (n-1) 3 = 999
(n-1)3= 987
n-1 = 329
n = 330
Now
sum
=330/2(12+999)
=165 x 1011
=166815

Answer 2

here is your answer