Answer: x=2
3x−9x+7−3=−8
Step 1: Simplify both sides of the equation.
3x−9x+7−3=−8
3x+−9x+7+−3=−8
(3x+−9x)+(7+−3)=−8
−6x+4=−8
−6x+4=−8
−6x+4−4=−8−4
−6x=−12
−6x
−6
=
−12
−6
x=2
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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
15/40 x 100 = 37.5
equation for percent decrease is diiference/original x 100.
answer:
explanation:
the area of the larger square is 36 (6*6), and the area of the smaller square is 16 (4*4). to find the ratio of the area, simply just put 16 over 36 and simplify.
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