
Rich G. answered 07/02/19
Experienced Algebra Tutor at High School and College Level
For the steamboat:
time = 5
rate = r (because we don't know the rate)
Since distance = rate * time
distance = 5*r
For the yacht
time = 2.5
rate = r+ 20 (because it's 20 knots faster than the steamboat)
Since distance = rate * time
distance = 2.5(r+20)
distance = 2.5r + 50
Since the distance traveled is equal for both the steamboat and the yacht, we can set the distance equations equal to each other
5r = 2.5r + 50
Now we can solve for r, which is the rate of the steamboat. Then we can take that value and solve for the rate of the yacht.