Question

mean of 8 numbers is 38.4 and the mean of seven of them is 39.2 what is the eight number

Answer 1

Hey here is your answer
Hope it helps

Answer 2

Answer:

The eighth number is 32.8

Step-by-step explanation:

Given :Mean of 8 numbers is 38.4

          Mean of seven of them is 39.2

To Find : What is the eight number

Solution:

$Mean = \frac{\text{Sum of all numbers}}{\text{Total no. of observations}}$

Since we are given that Mean of 8 numbers is 38.4

So, $38.4 = \frac{\text{Sum of 8 numbers}}{8}$

$38.4 \times 8=\text{Sum of 8 numbers}$

[tex]307.2 =\text{Sum of 8 numbers}[/tex]

Mean of seven of them is 39.2

So,  $39.2 = \frac{\text{Sum of 7 numbers}}{7}$

$39.2 \times 7=\text{Sum of 7 numbers}$

[tex]274.4 =\text{Sum of 7 numbers}[/tex]

So, Eight number = Sum of 8 numbers - Sum of 7 numbers

                             = 307.2  - 274.4

                             =32.8

Hence the eighth number is 32.8