VTMO 2026 - Grade 6 - Semifinal - SET 9 - Self-study Question 24

Find the arithmetic mean of the following numbers: $$\frac 11,\quad\frac{1+2}{2},\quad\frac{1+2+3}{3},\quad\ldots,$$ $$\frac{1+2+\cdots+47+48}{48},\quad\frac{1+2+\cdots+48+49}{49}.$$