Answer:
a) 61.2, b) 38.4 and c) 4.98
Step-by-step explanation:
Given:
The mean width of 12 I-Pads is 5.1 inches.
The mean width of 8 Kindles is 4.8 inches.
Question asked:
a. What is the total width of the I-Pads?
b. What is the total width of the Kindles?
c. What is the mean width of the 12 I-Pads and 8 Kindles?
Solution:
<u>As we know:</u>
<u />![Mean =\frac{Sum\ of\ observations}{Number\ of\ observations}\\ \\ Mean\ width =\frac{Sum\ of\ width\ of\ all \ I-pad}{Number \ of\ I-pad}](https://tex.z-dn.net/?f=Mean%20%3D%5Cfrac%7BSum%5C%20of%5C%20observations%7D%7BNumber%5C%20of%5C%20observations%7D%5C%5C%20%5C%5C%20Mean%5C%20width%20%3D%5Cfrac%7BSum%5C%20of%5C%20width%5C%20of%5C%20all%20%5C%20I-pad%7D%7BNumber%20%5C%20%20of%5C%20I-pad%7D)
![5.1=\frac{Sum\ of\ width\ of\ all\ I-pad}{12} \\ \\ By \ cross\ multiplication\\ \\ Sum\ of\ width\ of\ all\ I-pad}=5.1\times1 2\\ \\ Sum\ of\ width\ of\ all\ I-pad}= 61.2](https://tex.z-dn.net/?f=5.1%3D%5Cfrac%7BSum%5C%20of%5C%20width%5C%20of%5C%20all%5C%20I-pad%7D%7B12%7D%20%5C%5C%20%5C%5C%20By%20%5C%20cross%5C%20multiplication%5C%5C%20%5C%5C%20Sum%5C%20of%5C%20width%5C%20of%5C%20all%5C%20I-pad%7D%3D5.1%5Ctimes1%202%5C%5C%20%5C%5C%20Sum%5C%20of%5C%20width%5C%20of%5C%20all%5C%20I-pad%7D%3D%2061.2)
a) Thus, the total width of the I-Pads are 61.2 inches.
![Mean\ width =\frac{Sum\ of\ width\ of\ all\ Kindles}{Number \ of\ Kindles}](https://tex.z-dn.net/?f=Mean%5C%20width%20%3D%5Cfrac%7BSum%5C%20of%5C%20width%5C%20of%5C%20all%5C%20Kindles%7D%7BNumber%20%5C%20%20of%5C%20Kindles%7D)
![4.8=\frac{Sum\ of\ width\ of\ all\Kindles}{8} \\ \\ By \ cross\ multiplication\\ \\ Sum\ of\ width\ of\ all \ Kindles=4.8\times8\\ \\ Sum\ of\ width\ of \ all\ Kindles}=38.4](https://tex.z-dn.net/?f=4.8%3D%5Cfrac%7BSum%5C%20of%5C%20width%5C%20of%5C%20all%5CKindles%7D%7B8%7D%20%5C%5C%20%5C%5C%20By%20%5C%20cross%5C%20multiplication%5C%5C%20%5C%5C%20Sum%5C%20of%5C%20width%5C%20of%5C%20all%20%5C%20Kindles%3D4.8%5Ctimes8%5C%5C%20%5C%5C%20Sum%5C%20of%5C%20width%5C%20of%20%5C%20all%5C%20Kindles%7D%3D38.4)
b) Thus, total width of the Kindles are 38.4 inches.
Combined width of both I-pad and Kindles = 61.2 + 38.4 = 99.6 inches
Combined number of observations = 12 + 8 =20
Combined mean of width of the 12 I-Pads and 8 Kindles = Combined width of both I-pad and Kindles
Combined number of observations
Combined mean of width of the 12 I-Pads and 8 Kindles = ![\frac{99.6}{20} =4.98\ inches](https://tex.z-dn.net/?f=%5Cfrac%7B99.6%7D%7B20%7D%20%3D4.98%5C%20inches)
c) Thus, the mean width of the 12 I-Pads and 8 Kindles is 4.98 inches.