Well to find this out you need to make an equation
s+7=j So for example if Johnny's sister is 15 then Johnny would be 22 because s(sister's age) +7(number of years difference between their ages)=22(Johnny's age)
It displays three type of glacial erosion, like the cirque that is created by the side wards erosion and pyramidal peak also called as the horn. And the presence of the Arêtes that is a narrow region of rocks that are separated by the two valleys. The three main type of the erosion process of the glaciers are of plucking, and abrasion and the freeze-thaw