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
Add the ratios together and divide them by 132. then times the number by the answer you get.
3+3+5=11
132÷11=12
12×3=36
12×3=36
12×5=60
so: 36:36:60
<span>Experimental probability is defined as the
ratio of the number of times an event occurs to the total number of
trials the activity is performed
In this case the number that the event occurred is 8 and the number of trials is 50, so the ratio is 8/50 = 4/25.
Then the answer is option B: 4/25
</span>
<span>3
--- </span>-2 = 8<span>
y
</span>3
--- = 8+2
y
3
--- = 10
y
3
3
y = ------
10