The table below shows the number of magazines read by students of Class X in a month. One frequency is unknown.
Number of magazines (x) : 10 20 30 40
Frequency (f) : 3 5 m 2
Answer the following questions related to the distribution.
(a) Write an expression for the total number of observations N and for ∑fx in terms of m. Clearly indicate each step of your working.
(b) The mean number of magazines read is known to be 25. Using the information in part (a), form an equation in m that represents this fact. Do not solve the equation.
(c) Without solving the equation, state whether the value of m will be greater than 5 or less than 5. Give a brief reason for your answer.