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:
y = 2x + 3
Step-by-step explanation:
3 is the constant
2 is the rate at which recieves
So, y = 2x + 3
Answer:
Area of equilateral triangle:36cm
Square area:12cm
Step-by-step explanation:
We need to find the corresponding relationship, it is not difficult to find that this is a simple quadratic function problem.
I used pictures to express the process. You can click to view. I'm not English either. I'm Chinese, but I believe that academics know no boundaries.
Answer:
The answer is 52.
Step-by-step explanation:
Subtract 56 by 4. You'll get 52.
Answer:
Step-by-step explanation:
-2(2)-1+1(1)-1(-1)
Do multiplication
-4-1+1+1
Now add/subtract
-5+2
-3
