Question

Find the class mark of the class $35 - 40$

Answer 1

Hint: Since given that the class mark in two different types, like the highest mark can be obtained is given as $40$ and then the lowest mark can be obtained is given as $35$ with these two given class marks we need to find the average mark of the class, hence we will make use of the average formula that sum of the given numbers divided by the total numbers count.

Complete step-by-step solution:
Since given that class mark of the class $35 - 40$. We can clearly see that the upper limit value is $40$ because which is the greater value and then the lower limit value is given as $35$ because this is the lesser value. Hence the average formula or also called as the midpoint of the two numbers formula is $\dfrac{{40 + 35}}{2}$ means $CM = \dfrac{{UL + LL}}{2}$ where CM is the class mark, UL is the upper limit given, and also LL is the lower limit given.
Hence further solving we get $CM = \dfrac{{40 + 35}}{2} \Rightarrow \dfrac{{75}}{2}$ using the addition operation.
Therefore, we have $CM = \dfrac{{75}}{2} \Rightarrow 37.5$ using the division operation.
Hence, we get the average class mark as $37.5$

Note: The inverse of multiplication method is called division. Like $x \times y = z$is multiplication thus the division sees as $x = \dfrac{z}{y}$. Like $CM = \dfrac{{75}}{2} \Rightarrow 37.5$. Making use of the upper and lower limits on the class count and using simple operations, we solved the given problem. Sometimes students make mistakes by assuming the class mark as mean, which is not true, class mark is the mid value for the given interval.