In a class of 60 student , the number of students who passed Biology 6 more than the number who passed chemistry. Every student passed at least one of the two subjects and 8 students passed both subjects
b = bio , c = chem , B = both
b = c + 6
b + c + B = 60 ... b + c = 52
substituting ... c + 6 + c = 52 ... c = 23
substitute back to find b