The ages, in years, of 50 teachers in a school are given below :

21 37 49 27 49 42 26 33 46 40 50 29 23 24 29 31 36 22 27 38 30 26 42 39 34 23 21 32 41 46 46 31 33 29 28 43 47 40 34 44 26 38 34 49 45 27 25 33 39 40

(a) Form a frequency distribution table of the data using the intervals : 21 - 25, 26 - 30, 31 - 35 etc.

(b) Draw the histogram of the distribution 

(c) Use your histogram to estimate the mode

(d) Calculate the mean age.