Question

A school has 63% percent girls and 37%, percent boys. If 23%, percent of the girls wears contacts and 42%, percent of the boys wears contacts, what percent of all students wears contacts?

Answer 1

30% students

Explanation:

Let x be the number of total students of a school.

63% are girls then total number of girls = (0.63)x

37% are boys then total number of boys = ( 0.37)x

Now 23% of girls wear contacts then total number of girls

= (0.63x) × 0.23

= (0.1449x)

And 42% of boys wear contacts then total number of boys wearing contacts

= (0.37x) ( 0.42)

= (0.1554)x

Total students wears contacts = ( 0.1449x) + (0.1554x)

= (0.3003x)

Percentage of students wear contacts =
`\frac{\text{total students wear contacts}}{\text{total students in school}}` × 100

=
`(0.03003x)/(x)` × 100

= 30%

All 30% students wear contacts.