Question

find the results between the sum of all integer between 20and 30from the sum of all integer from 20to 30​

Answer 1

Answer:

$sum \: of \: all \: integers = \frac{n}{2}( {2a + (n - 1)d}) \\ = \frac{10}{2} \times (2 \times 20 + (10 - 1)1) \\ = 5 \times 49 \\ = 245$