Two boats leave port at the same time. One goes west and the other south. The speed of the southbound boat is 5 mph more than the westbound boat. After 3 hours the boats are 27 miles apart. Find the speed of the southbound boat. Round to the nearest tenth of a mile per hour.

Westbound boats speed = X

Southbound boats speed = X + 5

In 3 hours they are 27 miles apart:

3X + 3 (x+5) = 27

Simplify:

3x + 3x + 15 = 27

Combine like terms:

6x + 15 = 27

Subtract 15 from both sides:

6x = 12

Divide both sides by 6:

x = 12/6

x = 2

Westbound was 2 miles per hour

Southbound was 2 + 5 = 7 miles per hour

Check:

2 miles per hour x 3 hours = 6 miles

7 miles per hour x 3 hours = 21 miles

21 + 6 = 27 miles