Answer:
speed of the boat = 100 mph
Step-by-step explanation:
Let x = speed of the boat
upstream speed = x - 4
downstream speed = x + 4
time = 24/(x - 4) = 26/(x + 4)
Cross multiply:
24(x + 4) = 26(x - 4)
24x + 96 = 26x - 104
104 + 96 = 26x - 24x
200 = 2x
x = 100 mph
6, 7, 8, and 9. just plug the X into the equation
To solve this you need to know Pythagorean theorem.
First, EG is 24, so the halfway points are 12. Knowing Pythagorean triples, you can use 5,12,13 and 12,16,20.
DF = 5+16
DF = 21
If you don't know Pythagorean triples, I have worked it out on the image attached.