What Is The Sum Of Natural Numbers Up To 200 Excluding Those Divisible By 5?

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Oddman Profile
Oddman answered
The sum of the numbers from 1 to N is N(N+1)/2.

The sum of the numbers from 1 to 200 is (200)(201)/2 = 100(201) = 20100

The sum of the numbers from 1 to 200 divisible by 5 is the sum of 5, 10, 15, ..., 200. This sum is 5 times the sum of the numbers from 1 to 40: 5(40)(41)/2 = 5(20)(41) = 4100.

Since we want the sum of the numbers to 200 exclusive of those divisible by 5, we want 20100 - 4100 = 16000.

Sana Profile
Sana answered
The sum of natural numbers upto 100, excluding those divisible by 5, is 4000. So the sum of natural numbers upto 200, excluding those divisible by 5, must be definitely a lot greater than 4000. So if the options are 20100, 4100 and 16000, it would be 20100.

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