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: (3-1)×(7+5)
Step-by-step explanation:
There are mainly several ways to get 24
- 2×12
- 3×8
- 4×6
- add all of them together
- complicated ones can include large numbers minus another large number
Use try-check-revise, to find the way that fits 24
For this question, we used 2×12, which results in (3-1)×(7+5)
Hope this helps!! :)
Please let me know if you have any questions.
Answer:
x=-4
Step-by-step explanation:
46 = -7x + 18
subtract 18 from each side to get:
28 = -7x
divide each side by -7 to get:
x = -4
Answer:
Sanchez-97
Washington-117
Step-by-step explanation:
