Answer:
D
Step-by-step explanation:
r = boat's rate
c = current's rate
1. A boat traveled in a river upstream for a distance of 30 miles. Travelling upstream, the current obstructs the movement, so the actual boat's rate is r - c mph.
If the boat took 4 hours to travel upstream, then

2. A boat traveled in a river downstream for a distance of 30 miles. Travelling downstream, the current helps the movement, so the actual boat's rate is r + c mph.
If the boat took 3 hours to travel downstream, then

So, we get the system
4r-4c=30
3r+3c=30
Answer:
There is no precise unit of happiness, there might be multiple things that directly contribute to well-being, there doesn't seem to be any method to compare the quantities of different benefits (All of the above.)
Step-by-step explanation:
She would approximately spend 60$ since 62 is less than 65 (half)
Answer:
It would be C
Step-by-step explanation:
since the whole area of the circle is 18 and the sector takes up one-fourth of the circle you would just divide 18 by 4 to get 4.5
Answer:
Innovate
Step-by-step explanation:
Straight forward