A crate holds 200 fruits, of which 15% are overripe. How many of the good fruits must be taken out of the crate so that the overripe ones make up 20% of what is left in it?

The overripe count never changes: 15% of 200 = 30. They must end up as 20% of the crate, so the crate must end up holding 30/0.20 = 150 fruits, which means 200 - 150 = 50 good fruits are taken out. Only the base is being shrunk here - the share rises because the bottom of the fraction falls. 10 reads the 5-point gap as 5% of 200. 30 quotes the overripe count itself. 40 is 20% of the untouched crate of 200.