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:
He was probably measuring himself without shoes on so with shoes it adds a inch to his Highth
Hope this helps in some way
The first five terms of the sequence are; 4,600, 4,550, 4,500, 4,450, 4,400 and the total predicted number of sold cars for the first year is 51,900 cars
<h3>Arithmetic sequence</h3>
- First month, a = 4,600 cars
- Common difference, d = -50 cars
First five terms;
a = 4,600
a + d = 4600 + (-50)
= 4600 - 50
= 4,550
a + 2d
= 4600 + 2(-50)
= 4600 - 100
= 4,500
a + 3d
= 4,600 + 3(-50)
= 4,600 - 150
= 4,450
a + 4d
= 4600 + 4(-50)
= 4,600 - 200
= 4,400
cars predicted for the twelfth month.
a + 11d
= 4600 + 11(-50)
= 4600 + 550
= 4,050
Total predicted number of sold cars for the first year:
Sn = n/2{2a + (n - 1)d }
= 12/2{2×4600 + (12-1)-50}
= 6{9200 + 11(-50)}
= 6(9,200 - 550)
= 6(8,650)
= 51,900 cars
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Answer:
4116
Step-by-step explanation:
2014
12000÷10=1200 (10%)
1200x3=3600
12000-3600=8400
2015
8400÷10=840
840x3=2520
8400-2520=5880
2016
5880÷10=588
588x3=1764
5880-1764=4116
There are 33/20 or 1.65 pounds left.
Given:
4 3/4 pounds of clay
1 1/10 pounds of clay for a cup
2 pounds of clay for a jar
Convert the mixed fraction into fractions.
4 3/4 = (4*4+3)/4 = 19/4
1 1/10 = (1*10+1)/10 = 11/10
2 = 2/1
19/4 - 11/10 = (19/4 *5/5) - (11/10 * 2/2) = 95/20 - 22/20
= (95-22)/20 = 73/20 or 3.65 pounds after making a cup
73/20 - 2/1 = 73/20 - (2/1 * 20/20) = 73/20 - 40/20 = 73 - 40 / 20 = 33/20 OR 1.65 pounds left after making a jar.
We can also convert the fractions into decimal numbers.
19/4 = 4.75
11/10 = 1.10
2/1 = 2.00
4.75 - 1.1 - 2 = 1.65 pounds left.
