Problem

Source:

Tags: Comc, 2018 COMC



Source: 2018 Canadian Open Math Challenge Part B Problem 4 Determine the number of $5$-tuples of integers $(x_1,x_2,x_3,x_4,x_5)$ such that $\text{(a)}$ $x_i\ge i$ for $1\le i \le 5$; $\text{(b)}$ $\sum_{i=1}^5 x_i = 25$.