Correct option is A
Given:
- Total students = 70,
- 20% of girls have spectacles,
- 40% of boys have spectacles,
- Total students with spectacles = 23.
Solution:
Let the number of boys in the class be x.
Then, the number of girls in the class is 70 - x.
Calculate the number of boys with spectacles:
Since 40% of boys have spectacles, the number of boys with spectacles is:
0.4 × x.
Calculate the number of girls with spectacles:
Since 20% of girls have spectacles, the number of girls with spectacles is:
0.2 × (70 - x).
Total students with spectacles:
The sum of boys and girls with spectacles is given as 23. So:
0.4x + 0.2(70 - x) = 23.
Simplify the equation:
Expanding the terms:
0.4x + 14 - 0.2x = 23,
0.2x + 14 = 23,
0.2x = 9,
x = 45.
Thus, the number of boys in the class is 45.
