This book contains over 500 problems (with solutions) accompanying the lectures 26 through 50 of our 50 Lectures for American mathematics Competitions books covering the following topics: Counting How to solve inequality Polynomial Geometric sequence Binomial theorem Gaussian function Geometry Parallelograms Logarithms Word problems (distance and speed) Geometry Trapezoids Substitution method Analytic Geometry Circles and lines Probability System of equations Diophantine equations Geometry Circles Geometry Menelaus and Ceva Theorems Cauchy inequality Congruence Series and sequences Recursion method Trigonometry applications Analytic Geometry Ellipse Analytic Geometry Hyperbola Complex numbers