Complete question :
The 100m dah times in the girl's track meet were normally distributed with a mean of 13 seconds and a standard deviation of 0.3 seconds.
Lana finished the race in 13.2 seconds . If 84 other girls ran in the event, approximately how many runners did she beat?
Answer:
21 runners
Step-by-step explanation:
Mean, μ = 13 seconds
Standard deviation, σ = 0.3
Lana's race time = 13.2
We find the proportion of runners who had race time above 13.2 ;
Proportion of who had race tune above 13.2
P(x > 13.2)
Obtain the Zscore
Zscore = (x - μ) / σ
Z = (13.2 - 13) / 0.3
Zscore = 0.2 / 0.3 = 0.6667
P(Z > 0.6667) = 0.25239 (Z probability calculator)
This is about 0.25239 * 100 = 25.24% = 25% (nearest percent)
Hence, Number of runners Lana beat = 25% of total runners ;
0.25 * 84 = 21
Hence, Lana beat about 21 runners
Answer:
A.
Step-by-step explanation:
Rotations preserve shape <u>and</u> size, but a dilation with a factor of 3, no matter where in the sequence of transformations it is, results in a shape 3 times larger. So rotation followed by the dilation will end up being a rectangle similar to the original but 3 times its size.
Answer:
B) 12.5%
Step-by-step explanation:
1. Find amount spent on clothes in July
$2800 * 8% = j
<em>j = $224</em>
2. Find amount spent of clothes in August
$224 + $126 = a
<em>a = $350</em>
3. Find the amount's percentage of the total
$350/$2800 = x
x = 0.125 = 12.5%
Answer: f(a-2) = 2a² - 14a + 28
Step-by-step explanation:
f(x) = 2x² - 6x + 8
you can take a-2 and substitute it for each x, which would look like this:
f(a-2) = 2(a-2)² - 6(a-2) + 8
then distribute those in ( )
f(a-2) = 2a² - 8a + 8 - 6a + 12 + 8
combine like terms
f(a-2) = 2a² - 14a + 28
