Question

find the sum of all natural number less than 200 ,which are not divisible by 5​

Answer 1

Answer:

16K

Step-by-step explanation:

All natural numbers less than 200, not divisible by 5,

Lets first find the sum of numbers divisible by 5,

=> First term, a = 5, common diff, d = 5 , last term l = 200

Using the formula to find nth term, = An = a + (n-1)d

=> 200 = 5 + (n-1)5

=> 195 = n-1(5)

=> 39 = n-1

=> n = 40

Now,

Using the summation formula, = Sn = n/2(a+l)

=> Sn = 40/2 ( 5+200 )

=> Sn = 20(205)

=> Sn = 4100

Now,

Lets find the sum of all numbers from 1 to 200

Sn = n/2 (a+l)

=> Sn = 200/2 ( 1+200 )

=> Sn = 100 (201)

= Sn = 20100

Now,

Subtract the sum of numbers divisible by 5 from the sum of all numbers from 1 to 200,

=> 20100 - 4100 = 16000

Therefore, the sum of all natural number less than 200 ,which are not divisible by 5​ is 16000

I hope it helps...