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3 years ago

If 18 , x , y , -3 are in A.P then find x + y.

Mathematics

1 answer:

AleksandrR [38]3 years ago

6 0

Answer:

Step-by-step explanation:

If this is an arithmetic progression, then there is a common difference.

-3-18 = -21

-21/3 = -7

18 - 7 = x

x = 11

11 - 7 = y

y = 4

4 - 7 = -3

x + y

11 + 4 = 15

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confidence level =99%

significance level =α= 0.01

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confidence interval $= 939.5 - 3.499 \times \frac{1441.21}{\sqrt{8}} \right)$ to $= 939.5 + 3.499 \times \frac{1441.21}{\sqrt{8}} \right)$

Confidence interval $−843.396\$ to $2722.396$

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