Concept:The total number of students is the sum of all the frequencies shown by the heights of the bars.Explanation:Read the height of each bar to find how many students obtained each mark.The frequencies are 3,2,5,5,5,10,4,3,1,2.Add them together: 3+2+5+5+5+10+4+3+1+2.This gives 40.So, 40 students in all took the test.Answer:A. 40
