The sum of the heights of all students in a class is 1,472 in. The mean height is 5ft 4 in . How many students are in the class

Question

I really don't understand it please help

 

Answer 1

Hi Cris!  I can help here.  

 

The concept we are working with here is the arithmetic mean.  The arithmetic mean, better known as "the average", is described by the following equation:  

 

X_avg = ∑x/N

 

Where X_avg is the mean, ∑x is the sum of all data, and N is the number of data points.  

 

In this case, we know that the mean is 5ft 4in, or 64in.  We also know that the sum of all data is 1,472in.  We rearrange the above equation to solve for N:

 

N = ∑x/X_avg

N = 1,472in / 64in

N = 23 students.

 

Hope this helps!

Answer 2

Total heights divided by # of students = mean height (i.e., average).

 

From this, you can compute the # of students.