Question

Find the sum of all three digit number which are multiple of7​

Answer 1

Answer:

70336

Step-by-step explanation:

Three digit natural number which are multiples of 7 are 105 , 112,119....994

There all are in the form AP

First term = 105

common difference = 112-105=7

Let 994 be the Nth term if AP

An = 994

105 + ( n-1) ×7 = 994

7(n-1)= 994-105

7(n-1) = 889

n-1 = 889 / 7

n-1= 127

n = 127+1= 128

Sum of all term if AP = 128/2 ( 105)

= 64×1099

= 70336

Thus , the sum of all three digit numbers which are multiples of 7 is 70336

Hope it helps you