Answer:
let x=rate of the rowing team in still water
x+4=rate of the rowing team with current
x-4=rate of the rowing team against current
travel time=distance/rate
..
90%2F%28x%2B4%29=10%2F%28x-4%29
90x-360=10x+40
80x=400
x=5 rate of the rowing team in still water=5 mph
Answer:
5/6 can´t be simplified
Step-by-step explanation:
Answer: 
Step-by-step explanation:
Given
Vertex of the parabola 
Focus of the parabola 
As the x coordinate of vertex and focus is same and focus lie below the vertex, therefore the parabola is the type of

distance between Vertex and focus is 1 unit

Parabola becomes

Answer:
x+20⩾50
Step-by-step explanation:
in inequality, the word at least means that is equal or more than. so that means that Allie might equal or more than 50 hours in the model but if you're to solve it, Allie will need 30 or more hours. and since she already has 20, add the 20.