**Question:**

The width of each of five continuous classes in a frequency distribution is 5 and the lower class limit of the lowest class is 10. The upper class limit of the highest class is

(a) 15

(b) 25

(c) 35

(d) 40

**Solution:**

(c) Let x and y be the upper and lower class limit of frequency distribution.

Given, width of the class = 5

=> x-y= 5 …(i)

Also, given lower class (y) = 10 On putting y = 10 in Eq. (i), we get

x – 10= 5 => x = 15 So, the upper class limit of the lowest class is 15.

Hence, the upper class limit of the highest class

=(Number of continuous classes x Class width + Lower class limit of the lowest class)

= 5 x 5+10 = 25+10=35

Hence,’the upper class limit of the highest class is 35.

Alternate Method

After finding the upper class limit of the lowest class, the five continuous classes in a frequency distribution with width 5 are 10-15,15-20, 20-25,

25-30 and 30-35.

Thus, the highest class is 30-35,

Hence, the upper limit of this class is 35.