Problem
COM-B1-M03-P004 Choose or Exclude
#4
★☆☆☆☆ Level 1 of 5
Explain why \(\binom{10}{3}=\binom{10}{7}\).
Choosing \(3\) elements determines the \(7\) not chosen.
Each choice of \(3\) elements corresponds to the choice of the \(7\) elements not taken. This is a bijection, so the numbers are equal.
Combinatorial explanation of symmetry.