Question #dd09d

1 Answer
Jun 21, 2017

875

Explanation:

The sum of the first n odd numbers is equal to n^2.

In order to find the sum of the odd numbers between 10 and 60, just find the sum of the odd numbers below 60 and subtract the sum of the odd numbers below 10.

Since there are 30 odd numbers below 60 (the sum of these odd numbers would be 30^2) and 5 odd numbers below 10 (the sum of these odd numbers would be 5^2), the answer is 30^2-5^2=900-25=875.