Question

A motorboat leaves a harbor and travels at an average speed of 15 mph

Answer 1

Answer:

30 miles

Step-by-step explanation:

We know

D = RT

Where

D is the distance

R is the rate

T is the time

Towards Island:

R = 15

Let time be x

So, we can write:

D = 15x

Return from Island:

R = 10

Let time be y

So, we can write:

D = 10y

Also, total time is 5 hours, so we can write:

x + y = 5   [equation 2]

Now, since the distance for both legs of the journey is equal, we can write:

Distance 1 = Distance 2

15x = 10y

Now we replace this equation with equation 2, so we get:

Equation 2: x + y = 5 or x = 5 - y

15x = 10y

15(5 - y) = 10y

75 - 15y = 10y

75 = 25y

y = 75/25

y = 3

Distance 2 = D = 10y

Replacing y with 3, we get:

D = 10y

D = 10(3)

D = 30

So, the distance to island is 30 miles