Answer: (x^2)/16 + (y^2)/25 = 1
Step-by-step explanation:
According to the problem we can figure out that the center of the ellipse is (0,0).
Since the foci is (0,3) and (0,-3) we know that the value of c is 3. The major vertices are (0,5) and (0,-5) so the value of a is 5.
If we put this into the equation a^2=b^2 + c^2, we get 25=9+ b^2
We get b^2 is 16
Now since we know that the ellipse is vertical because the x value didn’t change, we know that the b^2 value comes first in the equation. Then the a^2 value which is 25.
In the third equation, the left side has ab.
You are solving for a, so you need a alone.
Dividing ab by b gives you a alone.
Answer: The third choice.
Answer: the speed of the current is 8 mph.
Step-by-step explanation:
Let represent the speed of the current
boat can travel 23mph in still water. This means that the total speed with which the boat travelled is (23 + x) mph.
Time = distance/speed
If it travels 248 miles with the current, it means that the time it took the boat to travel with the current is
248/(23 + x)
in the same length of time it travels 120 miles against the current. This means that the total speed with which the boat travelled is (23 - x) mph. The time it took the boat to travel against the current is
120/(23 - x)
Since the time is the same, it means that
248/(23 + x) = 120/(23 - x)
Cross multiplying, it becomes
248(23 - x) = 120(23 + x)
5704 - 248x = 2760 + 120x
120x + 248x = 5704 - 2760
368x = 2944
x = 2944/368
x = 8 mph
The answer is 72 because 720 divided by 10 is 72.
