To solve this problem you must apply the proccedure shown below:
1. You must apply the Law of Cosines, as you can see in the figure attached. Then:
- The first ship travels at
in for two hours. Therefore, the side
is:

- The second ship travels at
for
. Therefore, the side
is:

- Now, you can calculate
:

The answer is: 
Answer:

Step-by-step explanation:
Given

Required
Determine the expression for s
The speed is calculated as:

Substitute S for speed

Let the number of books be b and the time be m.
The expression becomes

Hence, the expression for the scenario is:

Here is the answer, with a picture of how you do it:)
Answer:
nothing much u
Step-by-step explanation: