The table shows the percentage of boy students and the difference between the…
2023
The table shows the percentage of boy students and the difference between the number of boys and girls in six different schools (A-F) during four years (2019-2022).
School \ Year | 2019 Boys (%) | 2019 Diff (*) | 2020 Boys (%) | 2020 Diff (*) | 2021 Boys (%) | 2021 Diff (*) | 2022 Boys (%) | 2022 Diff (*) |
A | 70 | 136 | 60 | 70 | 75 | 184 | 60 | 86 |
B | 40 | 84 | 48 | 18 | 45 | 48 | 60 | 90 |
C | 44 | 60 | 55 | 24 | 60 | 52 | 56 | 24 |
D | 44 | 84 | 57 | 84 | 55 | 72 | 65 | 192 |
E | 75 | 280 | 60 | 136 | 70 | 264 | 66 | 224 |
F | 44 | 90 | 56 | 96 | 65 | 228 | 45 | 84 |
Note: Difference (*) means the difference between the number of boys and girls.
Taking all four years together, what is the average number of boys appearing for the exam from school E?
- A.
424
- B.
434
- C.
438
- D.
454
Show answer & explanation
Correct answer: C
To find the average number of boys from School E, calculate the boy count for each year using the formula: Boys = Difference × [Percentage / (2×Percentage - 100)].
2019: 280 × (75 / 50) = 420 boys
2020: 136 × (60 / 20) = 408 boys
2021: 264 × (70 / 40) = 462 boys
2022: 224 × (66 / 32) = 462 boys
Total boys = 420 + 408 + 462 + 462 = 1752.
Average = 1752 ÷ 4 = 438.