There is a formula for this:
Time = (Worker1 Time * Worker2 Time) / (Worker1 Time + Worker2 Time)
Time = (12 * 8) / (12 + 8)
Time = 96 / 20
Time = 4.8 Hours
Source:http://www.1728.org/work.htm
Directly proportional or positively correlated
Hopes this helps:
Answer: D.
1. Simplify 12/18 to 2/3.
2/3 = 16/24
2. Simplify 16/24 to 2/3.
2/3 = 2/3
3. Some both sides equal, there are infinitely many solutions.
Your answer is A. Organ systems must interact with one another.
Hope I helped :)
