How should "a month and ten days from now" be interpreted?
Solution 1:
As you so rightly point out, this could be ambiguous.
The most natural thing to do would be to take them in the order specified. So first go a month from today, and then go 10 days. This goes to March 30th.
As a general presumption, take the operations in the order specified.
What is a month and 10 days from May 31st? A month from May 31st is June 30th, and the extra 10 days brings us to July 10th.
Whoever wrote this expression should have been more precise, and expressly stated how to deal with months of differing length. If he did not, you can only do your best.
A somewhat similar problem is, what is one year after February 23rd 2015? It is February 23rd 2016. However what is one year after February 24th 2015? It is February 25th 2015. This is because the extra day in a Leap Year is counted as falling on February 24th.