There are 720 boys in a school and 700 girls. The probability that a girl chosen at random studies french is 3/5 and the probability that a boy chosen at random studies french is 2/3. What is the total number of students in the school that study french?
The probability that a girl chosen at random studies french is 3/5. This means that out of 700 girls at the school, three fifths (3/5) girls study french. To find out how many girls study french we must find three fifths of 700. To do this we multipy 700 by 3/5. (If the student does not understand this, I would explain that to find three fifths of 700 we must first find one fifth (1/5) by dividing by 5, which is the same as multipying by 1/5. Then we must find three fifths by mutiplying this number by 3. This is the same by multiplying by 3/5).
700 x 3/5 = 420 girls therefore study french. Its the same working out for boys 700 x 2/3 = 480 boys study french. Therefore the total number of students that study french is 420 + 480 = 900 students.
ANSWER = 900 (3 marks)
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