Answer:
Average velocity is 32 miles/hr.
Step-by-step explanation:
Given that a particle moves on a line away from its initial position so that after t hours it is 
miles from its initial position.
We have to find the average velocity of the particle over the interval [1, 4].
As, average velocity is the change is position over the change in time.
∴ 
=
Hence, average velocity is 32 miles/hr.
Answer:
2 km/h
Step-by-step explanation:
Let x represent the speed of the river current, t₁ be the time spent rowing against the current and t₂ be the time spent rowing with the current.
Since the speed of the still water = 20 km/h.
The speed of rowing against the current = (20 - x)
The speed of rowing with the current = (20 + x)
We know that velocity = distance / time. Hence time = distance / velocity
t₁ = 36 / (20 - x)
t₂ = 22 / (20 + x)
but t₁ + t₂ = 3 hours
Therefore:
3 = 36 / (20 - x) + 22 / (20 + x)
multiply through by 400 - x²
3(400 - x²) = 36(20 + x) + 22(20 - x)
1200 - 3x² = 720 + 36x + 440 - 22x
3x² + 14x -40 = 0
This gives x = -6.7 or x = 2
x cannot be negative therefore x = 2 km/h
The speed of the river current is 2 km/h
Answer:
C
Step-by-step explanation:
it goes in 0.1
hope it helps
We break all the bracket out :
-0.75 + 2/5 + 0.4 - 3/4
2/5 = 0.4
-3/4 = -0.75
So, we have : -0.75 + 0.4 + 0.4 - 0.75
= (-0.75 - 0.75) + (0.4 + 0.4) = -1.5 + 0.8 = -0.7
We need a number to complete
Since we have
And so the expanded square is
