1:40 because if we think of this just like a fraction

that simplifys down to

and because fraction simplifications are similar (related to each other) we can concur that these would be too.
Enjoy!=)
Answer:
Null hypothesis is rejected. Standard deviation is > 8 miles per hour
Step-by-step explanation:
σ [Population standard deviation] = 8 , s [sample standard deviation] = s
n [no of items] = 8
H0 [Null] : σ = 8 ; H1 [Alternate - Right Tail] : σ > 8
χ2 = (n - 1) . s^2 / σ^2
= 49 x (10.5)^2 / 82 = 5402.25 / 64
χ2 = 84.410
df [degree of freedom] = n -1 = 50 - 1 = 49
P value (χ^2 49 > 84.410) = 0.00125
p = 0.0013
p < α ie 0.05
So, H0 is rejected
Hence we state that standard deviation is > 8 miles per hpur
True
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A closed circuit basically means everything is connected by wires and for this setup every device receives electricity making this true
Total tickets sold :
14 + 6 = 20
fraction of child tickets sold = 14/20
then, we convert this fraction to %.
14/20 = 70/100
( multiply by 5 )
percentage = 70%