Question

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 :

(i) how many pupils in all, wear spectacles?

(ii) what percent of the total number of pupils wear spectacles?

Answer 1

Total number of pupils = 1200

No.of. boys = 900

and no. of girls = 1200 - 900 = 300

No. of. boys who wear spectacles

= 20% of 900 = `20/100 xx 900 = 180`

No.of. girls who wear spectacles

`= 30% of 300 = 30/100 xx 300 = 90`

(i) ∴ Total number of pupils who  were spectacles = 180 + 90 = 270

(ii) Percentage of pupils who were spectacles

`= (270 xx 100)/1200 = 270/12 = 22.5%`