Question

find the sum of all three digit numbers between 300 to 700 which are divisible by 11

Answer 1

Answer: 18018

Step-by-step explanation:

First number to be divisible by 11 after 300 is 308

Last number to be divisible by 11 before 700 is 693

So in an AP

a=308

Last term=693

Last term = a+(n-1)d

d=11

693=308+(n-1)11

35=n-1

n=36

Sn=n/2(2a+(n-1)d)

18(616+ 385)

answer =18018

Answer 2

Answer:

Answer is 18018

Step-by-step explanation:

first number to be divisible by 11 after 300 is 308

last number to be divisible by 11 before 700 is 693

So, in AP

a=308

Last term=a+(n-1)d

d=11

693=308+(n-11)11

35=n-1

n=36

Sn=n/2(2a+n-1)d

18(616+385)

=18018 ans