From the top of a platform 5 m high, the angle of elevation of a tower was 30°. If the platform was positioned 40√3 m away from the tower, how tall was the tower?
The initial ratio of sugar to flour in a dough was 2 : 7. To 9 kg of the dough John added more sugar to make the sugar to flour ratio 2 : 5. How much sugar did John later add?