X^2 +6x-6=0 taking -6 to cross the equal sign
x^2+6x=6 by completing squ.
x^2 +6x+ 9= 6+9
x^2 +6x +9 =15
(x+3)^2= 15
x+3= 15^0.5
x= 3,87298-3 or -3.87298-3
x= 0.87298 or -6.87298
Whats the problem?
756/35=21,6
Answer:
okayyyyyyyyyyyyy
Step-by-step explanation:
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
Yeah sure, but i need to see the picture to get your answer
