Sum of 10s

What this probability question tests

This is a medium-difficulty probability problem that asks you to reason about the likelihood of a combined outcome across multiple discrete choices. It rewards careful enumeration of the sample space and the event of interest, rather than heavy computation.

To solve problems like this, you need to identify the range of possible values for the objects being chosen, determine when the constraint (in this case, a three-digit sum) is satisfied, and count the favorable outcomes relative to the total. The key is setting up the problem clearly: what exactly can each number be, and what sums meet the condition?

• Discrete uniform probability over a finite set
• Counting favorable outcomes and total outcomes
• Working with constraints on sums of random variables