Question

find the sum of find the sum of the sum of all multiples of 7 lying
between hundred and thousand ​

Answer 1

A.P=105, 112 , 119 .....994

994 = 105 +(n-1)7

994-105=(n-1)7

127 = n-1

n=128

Sum = 128/2(105+994)

=64(1099)

=63721

Answer 2

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