Question

find the sum of the multiples of the 3, lying between 200 and 300.

Answer 1

Sn= n÷2(a+an)
a=201
an=a+(n-1)d
d=3
n=34
an=201+(34-1)3
an=201+33×3
an=201+99
an=300
Sn=34÷2(201+300)
Sn=17(501)
Sn=8517

Answer 2

Answer:

refers to the attachment