Amir and Quader rode their scooter a distance of 50 meters to Teen Summit. Amir rode his scooter at a rate of 2 meters every second. Quader started 10 meters ahead and rode 3 meters every 2 seconds.

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.