I need a step-by-step process of how to solve this I know the answer but I need to know exactly how to solve these kinds of questions so I know how to do it for a test:

A large ship is being towed by two tugs. The larger tug exerts a force which is 25 percent greater than the smaller tug, and at an angle of 30 degrees south of west.
Which direction must the smaller tug pull to ensure that the ship travels due west?

Question

I need a step-by-step process of how to solve this I know the answer but I need to know exactly how to solve these kinds of questions so I know how to do it for a test: 

A large ship is being towed by two tugs. The larger tug exerts a force which is 25 percent greater than the smaller tug, and at an angle of 30 degrees south of west.
Which direction must the smaller tug pull to ensure that the ship travels due west?

anonymous · Answer

First you want to make a co-ordinate and label your origin. |dw:1397361900032:dw|

anonymous · Answer

Than you want to draw a diagram. |dw:1397361955654:dw|