To approximate the P(x<27) we need to find the z-score of the data, this will be given by:
z=(x-μ)/σ
where:
μ-mean
σ-standard deviation
x=27, μ=32, σ=4
z=(27-32)/4
z=-5/4
z=-1.25
thus
P(x<27)=P(z<-1.25)
=0.1056
=10.56%
Answer: 10.56%
Answer:
x = 10
Step-by-step explanation:
You can try the answers to see which works. (The first one does.)
Or, you can solve for the variable:
Divide by 75
... (1/5)^(x/5) = 3/75 = 1/25
Recognize that 25 = 5^2, so ...
... (1/5)^(x/5) = (1/5)^2
Equating exponents, you have
... x/5 = 2
... x = 10 . . . . . multiply by 5
_____
You can also start by taking logarithms:
... log(75) +(x/5)log(1/5) = log(3)
... (x/5)log(1/5) = log(3) -log(75) = log(3/75) = log(1/25) . . . . simplify the log
... x/5 = log(1/25)/log(1/5) = 2 . . . . . simplify (or evaluate) the log expression
... x = 10 . . . . . multiply by 5
_____
"Equating exponents" is essentially the same as taking logarithms.
Answer:
D. Putting money away for retirement
