Question

In Arithmetic progression way,question

Answer 1

Answer:

70336

Step-by-step explanation:

3 digit numbers 100 to 999

first term a =105

last term L=994

common difference d=7

to find number of terms

tn =a+(n-1)d

994=105+(n-1)7

994-105=7n-7

889=7n-7

889+7=7n

896=7n

n=128

to find sum

Sn=n/2(a+L)

= 128/2(105+994)

= 64(1099)

Sn=70336