a) Arithmetic mean mark First add all the values together (88+80+75+70+38+45+70+60+60+50) and divide them by the number of values (10). Which would equal to 63.6
b) Modal Mark This is the mode of the values (the value that appears most often in the set of data values) which would be 70 and 60
c) The Third Quartile Not too sure how to explain so I included an attachment to work it out
Hope this is all correct or at least helps you out :)