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
Use Pythagorean theorem
a^2 + b^2 = c^2
12^2 + 35^2 = c^2
144 + 1225 = c^2
1369 = c^2
Sqrt 1369 = c
37 = c
Answer:
The drama club bought 35 t-shirt
Step-by-step explanation:
Let
t-shirt = x
Sweatshirt = y
Total cost = $795
They purchase 20 more tshirts than sweatshirts
x = y + 20
The equation is:
12x + 25y = 795
12(y + 20) + 25y = 795
12y + 240 + 25y = 795
37y = 795 - 240
37y = 555
y = 15
Substitute y = 15 into
x = y + 20
x = 15 + 20
x = 35
t-shirt = 35
Sweatshirt = 15
The drama club bought 35 t-shirt
"The intersection (∩) of a pair of sets (G and H) is a third set (I) composed by the elements that belong, at the same time, to both given sets."
According to this definition:
Given the sets:
G = {3, 7, 8, 9}
H = {2, 5, 7, 8}
The Intersection is:
G ∩ H = I = {7, 8}
:-)
Answer:
the height is : 2365.48 m
Step-by-step explanation:
hello :
h(t) = − 4.9 t 2 + 211 t + 94 .
the vertex of this parabola is : (-b/2a , h(-b/2a) when : a= -4.9 and b=211
-b/2a = -(211)/2(-4.9) = 21.53
h(21.53) = -4.9(21.53)²+211(21.53)+94 = 2365.48 m
