Question

Using histogram, a frequency polygon is plotted as shown below.
If the area of frequency polygon is 100 $uni{t}^2$ and class length are same for all the classes, what is the length of a class interval?

• A. 15 unit
• B. 10 unit
• C. 5 unit
• D. 0.5 unit

Answer 1

The correct option is C 5 unit

As shown in the figure, the height of the bar = 10 units

Area of the histogram = Area of the frequency polygon = 100 $unit{s}^2$

Both bars are of the same equal length so we can take them as a whole rectangle.

Let x is the length of a class interval ,

Area of rectangle = $2x\times 10$ = Area of frequency polygon = 100 $uni{t}^2$

$⟹20\times x=100$
$\to x=5$