Here,
From the graph

Students with 3.0 grade = 450

Students with 3.3 grade = 300

Students with 3.7 grade = 225

Students with 4.0 grade = 150

Total students in the year 1950 with 3.0 and above grades = 450 + 300 + 225 + 150 = 1125

Thus, students with grades less than 3.0 = 3000 - 1125 = 1875

percentage = \(\frac{1875}{3000} * 100\)% = 62.5%
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why cant we just add the number of students that scored below 3.0 Grade point and then divide it by 3000. Why do we need to subtract the total and the students who scored atleast 3.0 Grade point