Jurong Primary School has three P5 classes. Class A has 30 students with an average score of 72 marks. Class B has 24 students with an average score of 80 marks. Class C has 6 students. The overall average score of all three classes combined is 75 marks. What is the average score of Class C?
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Worked Solution
Step 1: Find the total marks for Class A.
30 × 72 = 2160 marks
Step 2: Find the total marks for Class B.
24 × 80 = 1920 marks
Step 3: Find the total number of students in all three classes.
30 + 24 + 6 = 60 students
Step 4: Find the grand total marks using the overall average.
60 × 75 = 4500 marks
Step 5: Find the total marks for Class C by subtraction.
4500 − 2160 − 1920 = 420 marks
Step 6: Find the average score of Class C.
420 ÷ 6 = 70 marks
The average score of Class C is 70 marks.
Correct answer: 70 marks
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