Find the sum of all 2 digit numbers divisible by 3.

1.	Find the sum of all 2 digit numbers divisible by 3.
Answer» All 2 digit numbers divisible by 3 are : 12, 51, 18, 21, ..., 99. This is an A.P. with a = 12 and d = 3. Let it contain n terms. Then, 12 + (n - 1) x 3 = 99 or n = 30. Required sum = 30/2 x (12+99) = 1665.

Answer»

All 2 digit numbers divisible by 3 are : 12, 51, 18, 21, ..., 99.

This is an A.P. with a = 12 and d = 3.

Let it contain n terms.

Then, 12 + (n - 1) x 3 = 99 or n = 30.

Required sum = 30/2 x (12+99) = 1665.

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