Question 6
a) Positive integers $a,b$ satisfy $56a=65b$. Prove that $a+b$ is composite.
b) The diagram shows a square of side 14 cm and two quarter-circles. Find the positive difference between the areas of regions (I) and (II), using $\pi=22/7$.
b) The diagram shows a square of side 14 cm and two quarter-circles. Find the positive difference between the areas of regions (I) and (II), using $\pi=22/7$.