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
Learn more about arithmetic sequence here:
brainly.com/question/25749583
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<u>Given </u><u>:</u><u>-</u><u> </u>
- Mrs. Smith left a 15% tip for a dinner that cost $62.40.
<u>To </u><u>find</u><u> </u><u>:</u><u>-</u><u> </u>
- About how much tip did Mrs. Smith leave?
<u>Solution</u><u> </u><u>:</u><u>-</u><u> </u>
The tip is 15% of $62.40 .
<u>•</u><u> </u><u>Calculating</u><u> </u><u>1</u><u>5</u><u>%</u><u> </u><u>of </u><u>$</u><u>6</u><u>2</u><u>.</u><u>4</u><u>0</u><u> </u>
- $ 62.40 * 15%
- $ 62.40 * 15/100
- $ 9.36
Answer:
sum of exterior angles of polygon = 360°
therefore,
z = 360 - (105+145)
z = 360 - 250
z = 110°
<span>75 kilograms
The equation given for BSA doesn't look correct, perhaps due to formatting issues involving a simple copy and paste without any proofreading afterwards. Doing a quick google search gives the Mosteller formula for BSA which is:
BSA = sqrt(W*H/3600)
This formula is quite likely the original target of the copy and paste since it has all of the correct values and it's likely that the square root symbol wasn't properly pasted, nor the horizontal bar indicating division. So I'll use the Mosteller formula in solving this problem:
First, solve for W, then substitute the known values and calculate:
BSA = sqrt(W*H/3600)
BSA^2 = W*H/3600
3600*BSA^2 = W*H
3600*BSA^2/H = W
3600*1.96^2/185 = W
3600*3.8416/185 = W
74.755 = W
So the weight of the adult is 75 kilograms.
If the incorrectly copied equation of Bâ˘Sâ˘A=Hâ‹…W3600 were to be used and if the missing operator between the W and the 3600 were a divide symbol, the calculated value would be 38 kg, which is rather light for someone 185 cm tall since the low end of healthy is 65 kg. And if the missing operator between the W and 3600 was a multiply, then the calculated weight would be 3 micrograms which is way too small for a human being, no matter how starved. However, the value calculated using the Mosteller formula would represent a BMI of 22 which is about average for a normal healthy adult.</span>