Question

Obtain the sum of all natural number which are lying between 10 and 100 and multiple of 5

Answer 1

Answer:

i)between 10-100=4905

Step-by-step explanation:

a=10 n=90 d=1

Sn= n/2[2a+(n-1)d]

=90/2[2(10)+(90-1)1]

=45(20=89)

=45(109)

=4905

Answer 2

Answer:

refers to the attachment