A hot air balloon is at an elevation of 3 700 feet. If the balloon decends at a rate of 45 feet in 1 1/2 minutes, how long would it take for the balloon to reach 1,600?

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.