80% of the pupils are girls. 70% of the girls and 80% of the boys wear watches. What percentage of the pupils do not wear watches?
| Girls |
Boys |
Total |
| 80% |
20% |
100% |
| Wear watches |
Do not wear |
Wear watches |
Do not wear |
|
| 56% |
24% |
16% |
4% |
100% |
Number of girls who wear watches
= 70% x 80%
=
70100 x 80%
= 56%
Number of boys who wear watches
= 80% x 20%
=
80100 x 20%
= 16%
Percentage of pupils who wear watches
= 56% + 16%
= 72%
Percentage of pupils who do not wear watches
= 100% - 72%
= 28%
Answer: 28%
