Question 48
A $20 \times 20$ grid is divided into 400 unit cells of size $1 \times 1$. Clara colors each cell black or white, then Isabelle cuts the grid into rectangles along grid lines. Every rectangle must contain at most 2 black cells. Isabelle gives Clara one chocolate for each rectangle containing 0 or 1 black cell.
Isabelle minimizes the number of chocolates, while Clara chooses her coloring to maximize it. How many chocolates will Isabelle give Clara?
Isabelle minimizes the number of chocolates, while Clara chooses her coloring to maximize it. How many chocolates will Isabelle give Clara?