Anime Girl, this is the solution:
We have a total of 70 students (male and female), in consequence:
• Students that got an A = 18
,
• Students that got a B = 28
,
• Stiudents that got a C = 24
• P(A or B) = A + B / Total students
• P(A or B) = 18 + 28/70
,
• P(A or B )= 46/70
,
• P(A or B) = 23/35 (Simplifying) or 0.66