The ages of three siblings are all consecutive integers. The sum of of their ages is 39.

The ages of three siblings are all consecutive integers. The sum of of their ages is 39.

Let the age of the youngest sibling be n. This means the second sibling is n + 1. This means the oldest/third sibling is n + 2.

So what we want is the sum of 3 consecutive integers equal to 39. We type this command into our search engine. We get:
n = 12. So the youngest sibling is 12.

The next sibling is 12 + 1 = 13
The oldest/third sibling is 12 + 2 = 14