Answer:
cosA = 
Step-by-step explanation:
cosA =
=
=
= 
Answer: LAST OPTION.
Step-by-step explanation:
1. You have the following equation:

2. Then you must solve for x, as following:

Therefore, as you can see above, the answer for the exercise is the last option.
Answer:
2.5 hours
Step-by-step explanation:
BB = 25 + (15x)2
SS = (20x)2
25 + 30x = 40x
10x = 25
x = 2.5
Answer:
I can't explain here since I can't write numbers.
Step-by-step explanation: