Ina class of 90 students 60% are girls and remaining are boys. Average marks of boys are 63 and thatofgirls are 70. What are
the average marks of the whole class?
This questions was previously asked in
SSC CGL 13th August 2021 Shift-2
Explanation:
- In a class of 90 students, 60% are girls, which is 54 girls. The remaining 36 are boys.
- Average marks for boys: 63
- Average marks for girls: 70
- To find the average marks for the whole class, calculate the weighted average.
1. Multiply average marks by the number of students for each group:
- Boys: \( 63 \times 36 = 2268 \)
- Girls: \( 70 \times 54 = 3780 \)
2. Sum these results for total marks:
- Total marks = \( 2268 + 3780 = 6048 \)
3. Divide by total number of students to get the average:
- Average = \( \frac{6048}{90} = 67.2 \)
- Option 3: 67.2
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