Question

Find the sum of all numbers lying between 10 and 100 that are divisible by 7.​

Answer 1

Answer:

Sn=728

Step-by-step explanation:

First number divisible by 7 is 14

AP--> 14,21,28,35,.................…..,98

a=14

d=7

an=a+(n-1)d

98=14+(n-1)7

98-14=(n-1)7

84/7=n-1

12+1=n

13=n

Sn=n/2(a+an)

Sn=13/2(14+98)

Sn=13/2*112

Sn=13*56

Sn=728

Hope it helps

Answer 2

Answer:

answer for the given problem is given