Answer:
Step-by-step explanation:
Answer:
Step-by-step explanation:
First let's find the value of 'p-q':
To find |p-q| (module of 'p-q'), we can use the formula:
Where 'a' is the coefficient of 'i' and 'b' is the coefficient of 'j'
So we have:
Now, we need to find the module of p and the module of q:
Then, evaluating |p-q|-{|p|-|q|}, we have:
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.
