Question

the sum of all numbers between 100 and 1000 which is divisible by 13 is​

Answer 1

Answer:

please mark it as a brainliest answer

Answer 2

Answer

37674

Step-by-step explanation:

Given : Number divisible by 13 between 100 and 1000

To find : Sum of numbers divisible by 13 between 100 and 1000

Solution : The number divisible by 13 after 100 is 104 ( under trial and error)

                i.e 13*8=104

    The last number divisible by 13 before 1000 is 988 (under trial and error)

          i.e 13*76 = 988

The total numbers divisible by 13 between 100 and 1000 is

           988-104 = 68

   i.e n-1 = 68

   Therefore n = 69

$S_{n}$ = $\frac{n}{2}$ (a+l)

     where a is the first term and l is the last term

      Now n = 69

               a = 104

                l = 988

Therefore $S_{n}$ = $\frac{69}{2}$ (104+988)

                                          = $\frac{69}{2}$ * 1092

                                          = 69 * 546

                                          = 37674