Question

find the sum of all two digit numbers divisible by 3 using suitable formula
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Answer 1

Answer:

[(99 - 12) / 3] + 1 = 30 numbers in total.

Step-by-step explanation:

Step 1. Find first and last:

First: 12 Last: 99

Step 2. Find all numbers

[(99 - 12) / 3] + 1 = 30 numbers in total.

Step 3. Apply the arithmetic series formula

Sum = n * (First + Last) / 2

Sum = 30 * (12 + 99) / 2 = 1665