B). It looks as though they factored it.
Answer:
$2000
Step-by-step explanation:
The amount of interest you pay (for simple interest) is the product of the original amount, the interest rate and the time in years. Let x be the original amount (how much money she borrowed):
720=x(0.09)(4)
720=0.36x
x=2000
Answer:
x =0
Step-by-step explanation:
Solve for x over the real numbers:
sqrt(x) = 0
Square both sides:
Answer: x = 0
Answer:
The minimum average speed needed in the second half is 270 km/hr
Step-by-step explanation
We can divide the track in two parts. For the first half of the track the average speed the car achieved was 230 km/hr and we need to make sure that the average speed of the full track is 250 km/hr. Then, we can calculate the average speed of the two parts of the track and force this to be equal to 250 km/hr. In equation, defining
as the average speed of the second half:

Solving for 

Therefore, achieving a speed of 270 km/hr in the second half would be enough to achieve an average speed of 250 on the track.