Jill left school and traveled toward the recycling plant at an average speed of 45 km/h. Huong left five hours later and traveled in the opposite direction with an average speed of 60 km/h. How long does Huong need to
travel before they are 330 km apart?

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.