Answer:
option (D) 16.5
Step-by-step explanation:
Data provided:
Sleep time of , X = 15.9 is at the 10th percentile
Standard deviation, σ = 0.5 hour
also,
10th percentile of normal distribution is
Z = F⁻¹(0.10)
or
Z = - 1.28 (Using Standard Normal distribution)
Now,

or
X = μ + ( σ × Z )
or
μ = X - ( σ × Z )
on substituting the respective values, we get
μ = 15.9 - 0.5 × (-1.28)
or
μ = 16.5
Hence, the correct answer is option (D) 16.5
Answer:
b=-2aH
Step-by-step explanation:
H=-b/2a
Apply cross multiplication
H×2a=-b
2aH=-b
In the question you are to find positive b not negative b so you have to take negative b to the left hand side of the equation to become positive b and take 2aH to the right hand side to become -2aH
therefore b=-2aH

Let's solve ~







Inequalities change when it is multiplied by -ve number
