How did the U. S coastline provide an advantage for the south during the civil war?

During the civil war, it became easy for southern people to have access to inland cities in the North. As they had complete control over the coastline, they started shipping goods to Europe. While North had no aces and most of its products were industrial, it was at a disadvantage.

part a. there were 250 teenagers surveyed (100% of tenagers = 250)therefore 1 % = 250/100 = 2.5 76% = 1% x 76 = 2.5 x 76 = 190 teenagers of the 250 surveyed liked burgerspart b: jane surveyed 25% (which is equal to 50 teenagers, i.e. a quarter of the teenagers surveyed is 50) to get 100% we simply get 4 quarters, i.e. multiply 50 by 4 = 200 teenagers were surveyed by jane. part c: it is impossible to give an example where a percentage is greater than 100%, since, by definition , percentage means "per 100".