Question

find the sum of natural numbers between 1 to 40 which are divisible by 4​

Answer 1

Answer:

the no.s are 4 8 12 16 20 24 28 32 36 40

therefote their sum is 220

Answer 2

Answer:

220

We have d=4,a=4,l=40

Now we know that

l = a+(n-1)d

So

40=4+(n-1)4

=36= (n-1)4

=9 = n-1

= 10 =n

Now Sn = n/2(a+l)

10/2(4 + 40)

5 × 44 = 220