Final answer:
The speed of the Prince Walter ship is found by setting up an equation that accounts for the difference in travel time and speed between the two ships, then solving for x.
Step-by-step explanation:
To solve for the speed of the Prince Walter ship, let's denote it as x. The Queen Sadie's ship travels at a speed of x + 15 mph. The Prince Walter ship left four hours earlier, so it has traveled for 6 hours by the time the Queen Sadie's ship has been traveling for two hours.
Using the formula distance = speed × time, we set up the equation for the distance covered by the Prince Walter ship as 6x and the Queen Sadie's ship as 2(x + 15). These distances add up to 230 miles because the ships are traveling in opposite directions.
We have the following equation: 6x + 2(x + 15) = 230. Solving for x gives us the speed of the Prince Walter ship.