The marks obtained by 35 students in a test in statistics (out of 50) are as below . 35,1,15,35,45,23,31,40,21,13,15,20, 47,48,42,34,43,45,33,37,11,13,27,18 ,12,37,39,38,16,13,18,5,41,47,43. Construct a frequency distribution table with equal class intervals, one of them being 10 - 20 ( 20 is not included )​