Answer:
Step-by-step explanation:
n ≥ -2 + 9
n ≥ 7
First term: a1 = 151
common difference: d = -14 (we decrease by 14 each time, eg, 151-14 = 137)
nth term of this arithmetic sequence is...
an = a1+d(n-1)
an = 151+(-14)(n-1)
an = 151-14n+14
an = -14n+165
This will be used in the formula below
Sn = n*(a1+an)/2
<span>Sn = n*(151+(-14n+165))/2
</span><span>S26 = 26*(151+(-14*26+165))/2 ... replace every n with 26
</span>S26 = -624
The final answer here is choice C) -624
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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%