In order to solve for a nth term in an arithmetic sequence, we use the formula written as:
an = a1 + (n-1)d
where an is the nth term, a1 is the first value in the sequence, n is the term position and d is the common difference.
First, we need to calculate for d from the given values above.
<span>a1 = 38 and a17 = -74
</span>
an = a1 + (n-1)d
-74 = 38 + (17-1)d
d = -7
The 27th term is calculated as follows:
a27 = a1 + (n-1)d
a27= 38 + (27-1)(-7)
a27 = -144 -----------> OPTION D
Answer: 0.4 which is choice C
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Work Shown
Focus on the "riverside high school" row only
A = number of twelfth graders = 200
B = number of students = 500
P = probability of picking a twelfth grader
P = A/B
P = 200/500
P = 2/5
P = 0.4
5:6
The fraction 85/102 goes to 5/6 so it is 5:6 or 5/6...
add d to both sides
c(a+b) = f + d
divide away c
a+b = (f+d)/c
subtract b from both sides:
a=[(f+d)/c]-b