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.
3 7/8 because looking at the ruler, the line is 7 of the 8. hope that’s helps!
The plane's airspeed is 140:)
Answer:
this isnt spanish
Step-by-step explanation:
Ask: When will (4w-5)(7-w) equal zero?
When 4w-5=0 or 7-w=0
Solve each of the 2 equations above
w = 5/4 , 7
