What were two ways the u. s. navy countered the u-boat threat?

1. using the convoy system where destroyers escorted transport ships across the Atlantic

2. beginning in June 1918, the Allies began laying a barrier of 70,000 mines in the North Sea, making U-boat access to the North Atlantic virtually impossible.

With the convoy system, large trade ships were boxed in by cruisers so if there happened to be an attack these ships could attack back. Since Germany attempted to block any trade at this time, the convoy system was essential to continue trade with Europe.

Explanation:

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".