Answer:
The speed from the observer is 8 mph.
Step-by-step explanation:
When the boat is going downstream with full force, its speed will be the one the oarsman can row on still water added by the flow of the river. In this case he can row the boat at speed of 3 mph, while the stream is 5 mph, so the speed from the observer standpoint is:

The speed from the observer is 8 mph.
First take the fractions and find their common denominator:

x 4 =

Now you can add the fractions:

Now add your whole numbers and the fraction:
1+1= 2 >> 2+

= 2

yards
Now subract 2

from 5:
5-2

=
2
yards
O+o+2>36
2o>34
o>17
o1>17
o2>19
o is equal to odd number
Answer:
There is a 55% chance that it won't rain.