Assign two variables for each problem, and write the equations. do not solve.

a cruise ship has 680 rooms. those with a view rent for $160 per night, and those without a view rent for $105 per night. one a night when the ship was completely occupied, revenues were $92,500. how many rooms of each type are on the ship?

need two variables and two equations. you do not have to solve this.

Lets make a be equal to the number of rooms with a view and b equal the number of rooms with out a view. Since the total number of rooms 680, you can make the equation a+b=680.  we also know the total cost per night of each of the rooms as well as the total amount of money received when all of the rooms were filled for one night making it so that we can write the equation 160a+105b=92500.  Since those two equation have the same a and b values, you can make a system of equations that looked like the fallowing:
 a+b=680
160a+105b=92500

I hope this helps.  Also, if you need to eventually solve it, you should get a=383.64 and b=296.36. 

40 & 50 in the right corner are the complementary angles as when placed in a sum (added together) they make 90°

The answer is e &