Question

The class mark of the class is 12 - 23 ​

Answer 1

Answer:

17.5

Step-by-step explanation:

class mark= upper class + lower class / 2

= 23+12/2 = 35/2

= 17.5

Answer 2

Answer:

Class Mark =lowerlimit+upperlimit2=lowerlimit+upperlimit2

For interval 20 – 30, substitute the values,

⇒⇒ Class Mark =20+302=20+302

Add the terms in the numerator,

⇒⇒ Class Mark =502=502

Divide numerator by denominator,

∴∴ Class Mark =25=25

For interval 30 – 40, substitute the values,

⇒⇒ Class Mark =30+402=30+402

Add the terms in the numerator,

⇒⇒ Class Mark =702=702

Divide numerator by denominator,

∴∴ Class Mark =35=35

Hence, the class mark for interval 20 – 30 is 25 and for interval 30 – 40 is 35.

Note: Students should always keep in mind that the class marks always lie between given class intervals, that is, it will be greater than the lower limit of class interval and less than the upper limit of the class interval. The class mark of any positive class interval cannot be negative. Students should be careful while doing addition and division. Students should not get confused when a class mark is asked as it is the same as the mid-value of the given class interval.