Speed, S = Distance (d) / Time (t) => S= d/t => t= d/S
Let the speed of boat in still water be x mph
Resulting speed upstream = x-4 mph for a distance of 30 miles
Resulting speed downstream = x-4 mph for a distance of 50 miles
Time taken in both distances is equal.
Therefore,
30/(x-4) = 50/(x+4) => 30(x+4) = 50(x-4) => 30x+120 = 50x-200 => 120+200 = (50-30)x => 20x = 320 => x=320/20 = 16 mph
The speed of boat in still water is 16 mph.
We can solve this problem by using the distance formula. The distance formula is: 
We can now put in values and solve.
16/25 = 0.64 = 64%
Another way to do it is to multiply top and bottom by 4
16/25 = (16*4)/(25*4) = 64/100 = 64%
Either way, the answer is 64%
I believe its B but I'm not completely sure
Answer:
the answer is not correct
there is a sign error under the radical
it should be 3^2 - 4(-8)(2) = sqrt(73) not sqrt(55i)
Step-by-step explanation:
