Question

If the class mark and class size of the class

Answer 1

Answer:

The class interval is: 20-30

Step-by-step explanation:

Let l be the lower class limit and u be the upper class limit.

Then according to given statement that class mark is 25

$\frac{l+u}{2} = 25\\l+u = 50\ \ \ Eqn\ 1$

And

Class size is 10

So, the second equation will be:

$u-l = 10\ \ \ \ Eqn\ 2$

Adding equation 1 and 2

$l+u+u-l = 50+10\\2u = 60\\\frac{2u}{2} = \frac{60}{2}\\u = 30$

Now putting u =30 in equation 1

$l+u = 50\\l+30 = 50\\l = 50-30\\l = 20$

A class interval is written in the form that lower limit comes first and upper limit comes second.

So,

20-30

Hence,

The class interval is: 20-30