It would be bias if Amalie just surveyed a small population of her class rather than the whole. Hope this helps!
Given:
Original price = 20
reduces selling price by 25% every month it's not sold.
First markdown month:
20 * (100%-25%) = 20 * 75% = 15
Second markdown month
15 * 75% = 11.25
Macy, employee gets a 50% discount off the current price.
11.25 * 50% = 5.625
11.25 - 5.625 = 5.625 or 5.63
The pre-tax price of the shirt for Macy will be $5.63
Given:
On the first day, she drove 650 miles in 10 hours.
On the second day, she got a later start and drove 540 miles in 8 hours.
To find:
Difference between average speed of second day and first day.
Solution:
We know that,
On the first day, she drove 650 miles in 10 hours. So, the average speed is
So, the average speed on first day is 65 miles per hour.
On the second day, she got a later start and drove 540 miles in 8 hours.
So, the average speed on second day is 67.5 miles per hour.
Difference between average speed is
Therefore, the average speed on the second day is 2.5 miles per hour is faster than first day.
We have two equations that were solved by Nikki and Jonathon:
Equating the above two:
⇒ 1.3x + 1.6 = -2.7x + 3.2
⇒ 4x = 1.6
⇒ x = 0.4
Hence, substituting the value of x in one of the equations we get:
y = 1.3×0.4 + 1.6 = 2.12
So the solution is (0.4, 2.12)
Jonathon's solution was (0.4, 2.12) and Nikki's was (2.25, 0.5). Hence Jonathon gave the correct solution.
Trapezoidal is involving averageing the heights
the 4 intervals are
[0,4] and [4,7.2] and [7.2,8.6] and [8.6,9]
the area of each trapezoid is (v(t1)+v(t2))/2 times width
for the first interval
the average between 0 and 0.4 is 0.2
the width is 4
4(0.2)=0.8
2nd
average between 0.4 and 1 is 0.7
width is 3.2
3.2 times 0.7=2.24
3rd
average betwen 1.0 and 1.5 is 1.25
width is 1.4
1.4 times 1.25=1.75
4th
average betwen 1.5 and 2 is 1.75
width is 0.4
0.4 times 1.74=0.7
add them all up
0.8+2.24+1.75+0.7=5.49
5.49
t=time
v(t)=speed
so the area under the curve is distance
covered 5.49 meters
