There are 20 students in a class and every student attended an examination. The lowest and highest marks scored by a student out of 100 is 32 and 88 respectively. It is found that 20 students are divided into 10 different groups of two each then the average of each of the 10 groups is same then what is the average marks obtained by the students if apart from the lowest and highest, every other score was a multiple of 3?