Answer:
-1,512,390
Step-by-step explanation:
Given
a1 = 15
Let us generate the first three terms of the sequence
For 
Hence the first three terms ae 15, 8, 1...
This sequence forms an arithmetic progression with;
first term a = 15
common difference d = 8 - 15 = - -8 = -7
n is the number of terms = 660 (since we are looking for the sum of the first 660 terms)
Using the formula;
![S_n = \frac{n}{2}[2a + (n-1)d]\\](https://tex.z-dn.net/?f=S_n%20%3D%20%5Cfrac%7Bn%7D%7B2%7D%5B2a%20%2B%20%28n-1%29d%5D%5C%5C)
Substitute the given values;
![S_{660} = \frac{660}{2}[2(15) + (660-1)(-7)]\\S_{660} = 330[30 + (659)(-7)]\\S_{660} = 330[30 -4613]\\S_{660} = 330[-4583]\\S_{660} = -1,512,390](https://tex.z-dn.net/?f=S_%7B660%7D%20%3D%20%5Cfrac%7B660%7D%7B2%7D%5B2%2815%29%20%2B%20%28660-1%29%28-7%29%5D%5C%5CS_%7B660%7D%20%3D%20330%5B30%20%2B%20%28659%29%28-7%29%5D%5C%5CS_%7B660%7D%20%3D%20330%5B30%20-4613%5D%5C%5CS_%7B660%7D%20%3D%20330%5B-4583%5D%5C%5CS_%7B660%7D%20%3D%20-1%2C512%2C390)
Hence the sum of the first 660 terms of the sequence is -1,512,390
Answer:
Step-by-step explanat số âm vì số âm < số dương mà nhiệt đọ càng thấp thì càng lạnhion:
The dealer paid 'C' for it. He decided to sell it for 10% more than C .
That would be (1.10 C) , and that's the $856.90 .
So the equation is . . . 1.10 C = $856.90
Divide each side by 1.10 : C = $856.90 / 1.10
<em>C = $779</em>
Answer:
$1.75
Step-by-step explanation:
Divide 28$ by 16 pieces for 1.75 a piece
Answer:
She'd have travelled 120 extra miles, 600 miles in total.
Step-by-step explanation:
480 : 8 = 60 --> 60 miles per hour
60 x 10 = 600 --> 600 miles in 10 hours at that speed
600 - 480 = 120 --> extra miles in the extra two hours at that speed
