Question

Sum of the natural numbers between 1 to 101 divisible by 2 or 5 is​

Answer 1

The natural number which are divisible by 2 and 5 are 10, 20, 30,........................,100 a=10 , d=10 , nth term= 100 Find sum and nth term an= a+* (n-1)d

100=10+(n-1)10

100=10+10n-10

100=10n

n=100/10

n=10

sn=n/2(a+l)

sn=10/2(10+100)

sn=5(110)

sn=550