The sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
Given,
18th term of an arithmetic sequence = 8.1
Common difference = d = 0.25.
<h3>What is an arithmetic sequence?</h3>
The sequence in which the difference between the consecutive term is constant.
The nth term is denoted by:
a_n = a + ( n - 1 ) d
The sum of an arithmetic sequence:
S_n = n/2 [ 2a + ( n - 1 ) d ]
Find the 18th term of the sequence.
18th term = 8.1
d = 0.25
8.1 = a + ( 18 - 1 ) 0.25
8.1 = a + 17 x 0.25
8.1 = a + 4.25
a = 8.1 - 4.25
a = 3.85
Find the sum of 20 terms.
S_20 = 20 / 2 [ 2 x 3.85 + ( 20 - 1 ) 0.25 ]
= 10 [ 7.7 + 19 x 0.25 ]
= 10 [ 7.7 + 4.75 ]
= 10 x 12.45
= 124.5
Thus the sum of the first 20 terms of an arithmetic sequence with the 18th term of 8.1 and a common difference of 0.25 is 124.5
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Answer: $16.5/hour
Step-by-step explanation:
The unit rate is the relationship between y and x if x = 1
660/40 = 16.5
That means, if x = 1, y = 16.5
Therefore, <u>$16.5/hour</u>
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Answer:
Ok I will help u
Step-by-step explanation:
The answer is A. 17 cm, 5 cm, 13 cm
For the triangle:
a+b > c
b+c > a
a+c > b
Check all choices:
<span>A. 17 cm, 5 cm, 13 cm
a = 17
b = 5
c = 13
17+5 = 22
22 > 13
5+13= 18
18 > 17
17+13=30
30>5
If you check other choices, you will see they are incorrect.</span>
Answer:
Step-by-step explanation:
