Answer:
The speed in still water is 5 miles per hour.
Step-by-step explanation:
distance with current = 90 miles
distance against current = 10 miles
speed in still water = s
speed of current = 4 mph
speed with current = s + 4
speed against current = s - 4
time = t
speed = distance/time
distance = speed * time
With current:
90 = (s + 4) * t
Against the current:
10 = (s - 4) * t
We have a system of equations:
90 = (s + 4) * t
10 = (s - 4) * t
90 = ts + 4t
10 = ts - 4t
Subtract the second equation from the first equation.
80 = 8t
10 = t
t = 10
10 = t(s - 4)
10 = 10(s - 4)
1 = s - 4
s = 5
Answer: The speed in still water is 5 miles per hour.
 
        
             
        
        
        
Area of parallelogram = base x height 
Area = 6 x 5 
 = 30 unit ^2
        
             
        
        
        
Answer:
<em>The base of the triangle = 9inches</em>
Step-by-step explanation:
<u>Explanation</u>:-
The area of the triangle =  square units
 square units
Given area of the triangle(A) = 54 square inches
Given the height of the triangle (h) = 12 inches
now  equating     
                           
now simplification, we get
                            6 b = 54
Dividing '6' on both sides, we get
                              b = 9 
The base of the triangle = 9 inches
<u>Conclusion</u>:-
<em>The base of the triangle = 9 inches</em>
 
        
             
        
        
        
Same here, we do a quick switcharoo on the variables first,
