The values of lung capacity are normally distributed with a mean of 3500 mL and a standard deviation of 300 mL.
23% of people have a lung capacity less than that of M. To determine the lung capacity of M, use the normal distribution table to find the corresponding z-score for 23%. This is equal to -0.74
If M's lung capacity is X, `(X - 3500)/300 = -0.74`
=> `X = 3500 - 0.74*300 = 3278`
M's lung capacity is 3278 mL.