Betty's Sweet Treats sells caramel apples each fall. This year, the apples are the same type as last year, but slightly larger. The owners are concerned that the larger apples could throw off the perfect balance between tangy apple and sweet caramel. Assuming that the apples are all similar and that the ratio of the heights of this year's apples to last year's apple is 6:5, find the ratio of the apples' volumes and the ratio of the apples' surface areas to be covered with caramel.