Question

find the sum of all natural of numbers lying between hundred and 500 which are exactly divisible by 8

Answer 1

Hello,

Numbers between 100 and 500 that are divisible by 8 = 104, 112, 120, ......496

So,
This is an AP, where

First term = a = 104

Common difference = d = 8

Last term = 496

So,

l = a + (n - 1)d

=> 496 = 104 + (n - 1)8

=> 496 = 104 + 8n - 8

=> 8n = 496 - 96

=> n = 400/8

=> n = 50

So, there are 50 terms between 100 and 500 that are divisible by 8.

So,

Sum of these terms = n/2 × (a + l)

= 50/2 × (104 + 496)

= 25 × 600

= 15000

HOPE IT HELPS

Answer 2

Answer:

refers to the attachment