Question

5.2, 8.3, 8.5, 7.7, 7.8, y; mean = 7.1

Answer 1

Answer:  The required value of y is 5.1.

Step-by-step explanation:  We are given to find the value of y such that the mean of the following numbers is 7.1 :

5.2,  8.3,  8.5,  7.7,  7.8,  y.

We know that

MEAN of a group of numbers is equal to the average of the numbers.

The total number of numbers in the given group = 6

and

the sum of all the numbers in the group

= 5.2 + 8.3 + 8.5 + 7.7 + 7.8 + y

= 37.5 + y.

So, according to the given information, the mean is given by

$\dfrac{37.5+y}{6}=7.1\\\\\Rightarrow 37.5+y=42.6\\\\\Rightarrow y=42.6-37.5\\\\\Rightarrow y=5.1.$

Thus, the required value of y is 5.1.

Answer 2

You know that to find the mean you add all the numbers and divide by how many numbers there are. So work backwards.

add all the numbers you have=37.3
Since you divided by 6, do the opposite 7.1 x 6 = 42.6
Now subtract the difference= 42.6 - 37.3 = 5.5