Answer:
B
Step-by-step explanation:
Use the quadractic equation, x=-b+or-sqrtb^2-4ac/2a, then simplify.
I'm really sorry that it looks messy, I don't know how to make my text look better :(
19/45 is 0.42222222 if you round that to the nearest thousandth you get 0.422.
Answer:
10 kph
Step-by-step explanation:
Find the speed of the current of the river.
20/(20 - c) + 180/(20 + c) = 8
20(20 + c) + 180(20 - c) = 8(400 - c^2)
8c^2 - 160c + 800 = 0
8(c^2 - 20c + 100) = 0
8(c - 10)^2 = 0
c = 10
The speed of the current of the river is 10 km/hour.
