Answer:
The speed of the current is 3 miles per hour
Step-by-step explanation:
The equations for rate (r), distance (d), and time (t) are ⇒ d = rt, r = d/t, = t = d/r
Let x = speed in still water
Let c = speed of the current
The main difference with these problems is rate needs to be expressed using two variables because moving upstream the current is against you and downstream it moves with you.
Distance Rate Time
Upstream x − c
Downstream x + c
The distance column with the numbers from the problem and the value for speed in still water for x.
Distance Rate Time
Upstream 4 5 − c
Downstream 16 5 + c
The column for time using the other two columns knowing that rate, distance ⇒ time = Distance Rate Time
Upstream 4 5 − c
5 − c
4
Downstream 16 5 + c
5 + c
16
“It takes as long …” from the problem means that the two times are equal to each other. So, the equation can be written as:
4/5− c = 16/5 + c ⇒ Solve by cross-multiplying ⇒ 5(4 + c) = 16 5( − c) ⇒ c = 3
Use the midpoint formula,
(x1+x2/2,y1+y2/2)
(-1-5/2,1-3/2)
(-6/2,-2/2)
(-3,-1)
Answer:
81y^4 - 16x^2, difference of squares.
Step-by-step explanation:
So we need to expand the following product:
(9y2-4x)(9y2+4x) = 9y2*9y2 + 4x*9y2 - 4x*9y2 -4x*4x = 81y^4 - 16x^2
And this type of product is the difference of squares.
Answer:
2. (1) 
3. (1) 
4. a) 
b) 
Step-by-step explanation:
Answer:
5 in^2
Step-by-step explanation:
The area of the sector will always be proportionate to the angle in the circle.
(The area of the sector / area of the circle) is equal to( the angle of the section divided by the angle of the circle)
The total degrees of a circle is 360
(area of the sector) = (60° / 360°) * 30 in^2
