Answer:
Step-by-step explanation:
The formula for determining the sum of the first n terms of an arithmetic sequence is expressed as
Sn = n/2[2a + (n - 1)d]
Where
n represents the number of terms in the arithmetic sequence.
d represents the common difference of the terms in the arithmetic sequence.
a represents the first term of the arithmetic sequence.
If a = 5, the expression for the sum of the first 12 terms is
S12 = 12/2[2 × 5 + (12 - 1)d]
S12 = 6[10 + 11d]
S12 = 60 + 66d
Also, the expression for the sum of the first 3 terms is
S3 = 3/2[2 × 5 + (3 - 1)d]
S3 = 1.5[10 + 2d]
S3 = 15 + 3d
The sum of the first 12 terms is equal to ten times the sum of the first 3 terms. Therefore,
60 + 66d = 10(15 + 3d)
60 + 66d = 150 + 30d
66d + 30d = 150 - 60
36d = 90
d = 90/36
d = 2.5
For S20,
S20 = 20/2[2 × 5 + (20 - 1)2.5]
S20 = 10[10 + 47.5)
S20 = 10 × 57.5 = 575
Revenue = $2000
Labour cost = 40 x 8 = $320
Percentage = 320/2000 x 100 = 16%
Answer: 16%
The hypotenuse of the right triangle measures 3 units.
<h3>
How to find the hypotenuse?</h3>
Here we know that both legs measure:

If we use the Pythagorean theorem, we will see that the hypotenuse H can be written as:

Then we conclude that the hypotenuse of the right triangle measures 9 units.
If you want to learn more about right triangles:
brainly.com/question/2217700
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Answer:
you're all good !!
Step-by-step explanation: