Answer:
B i think
Step-by-step explanation:
Jessica bought 2.25 yards more material than Derek. Hope this helped!
Vertices (3,0),(-3,0) co-vertices (0,-5),(0,5)
transverse axis (line passing vertices) is on(or parallel to) x-axis then formula is
(x-h)^2/a^2 - (y-k)^2/b^2 = 1
..notice.. x^2 is on positive / y^2 is on negative
center (h,k) is midway between vertices = (0,0)
we have h = k = 0 and now formula is
x^2/a^2 - y^2/b^2 = 1
a is the distance from a vertex to center = 3
b is the distance from a co-vertex to center = 5
the formula is
x^2/3^2 - y^2/5^2 = 1 ... answer is the 1st
40 questions
Reasoning: 36/40=0.9
To solve this we are going to use the formula for speed:

where

is the speed

is the distance

is the time
Let

be the speed of the boat in the lake,

the speed of the boat in the river,

the time of the boat in the lake, and

the time of the boat in the river.
We know for our problem that <span>the current of the river is 2 km/hour, so the speed of the boat in the river will be the speed of the boat in the lake minus 2km/hour:
</span>

We also know that in the lake the boat<span> sailed for 1 hour longer than it sailed in the river, so:
</span>

<span>
Now, we can set up our equations.
Speed of the boat traveling in the river:
</span>

But we know that

, so:

equation (1)
Speed of the boat traveling in the lake:

But we know that

, so:

equation (2)
Solving for

in equation (1):


equation (3)
Solving for

in equation (2):




equation (4)
Replacing equation (4) in equation (3):


Solving for

:






or

We can conclude that the speed of the boat traveling in the lake was either
6 km/hour or
5 km/hour.