Out Of 1200 Pupils In A School, 900 Are Boys And The Rest Are Girls. If 20% Of The Boys And 30% Of The Girls Wear Spectacles, Find How Many Pupils In All Wear Spectacles And What Percent Of Total Number Of Pupil Wear Spectacles

Given: No. of people in school = 1200

No. of boys in school = 900

20% of boys and 30% of girls wear spectacles 

To find: How many people in  all wear spectacle and what percentage of people wear spectacles
 

Solution:

Number of girls in a school = 1200 - 900 =300

If that boys = 20% who wear spectacles .

If the girls = 30% who wear spectacles .

Total number of pupils wear who spectacles.

Boys = $\frac{20}{100} \times 1200 =20 \times12$
          =180

Girls = $\frac{30}{100} \times 300 =30 \times 3$

         =90

Total number of pupils who wear spectacles = 180 + 90 =270

Percent of pupils who wear spectacles

= $\frac{270}{1200} \times100 $

=$\frac{270}{12}$

=22.5%