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
The answer would be 63 bc 46+71= 117 then a triangle usaually equals 180 so 180 -117=63!!
Answer: $85,000
Step-by-step explanation:
Given : In a given population of two-earner male-female couples, male earnings have a mean of $40,000 per year and a standard deviation of $12,000.
Female earnings have a mean of $45,000 per year and a standard deviation of $18,000.
If C denote the combined earnings for a randomly selected couple.
Then, the mean of C will be :-
Hence, the mean of C = $85,000
290
hopefully i could help ;)
Answer:
$246.75
Step-by-step explanation:
A student earns $11.75 for 1 hour
If she works for 21 hours this month then the total amount earned can be calculated as follows
= 11.75 × 21
= 246.75
Hence the total amount earned this month is $246.75
