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
To convert a percentage to a decimal you move the decimal two places to the left. Therefore:
15.% becomes .15
You then multiply this decimal to the number you are trying to find the percentage of.
.15 × 60 = 9.
9 is 15% of 60.
Answer:
13g
Step-by-step explanation:
10g + 8g = 18g
18g - 5g = 13g
Answer:
You need to buy 5 bags of flour
Step-by-step explanation:
Each bag is 500g and needs 2.5kg.
If we replace 2.5kg it goes to 2500g.
2500g / 500g = 5 bags
