There are 115 pupils in a basketball court.
27 of the boys and
35 of the girls wear spectacles, there are 68 pupils in the basketball court who do not wear spectacles. How many girls wear spectacles?
| |
Boys |
Girls |
Total |
| Do not wear spectacles |
5 u |
2 p |
68 |
| Wear spectacles |
2 u |
3 p |
47 |
| Total |
7 u |
5 p |
115 |
Number of pupils who wear spectacles
= 115 - 68
= 47
5 u + 2 p = 68 --- (1)
2 u + 3 p = 47 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 136 --- (3)
(2)
x 5 10 u + 15 p = 235 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 235 - 136
15 p - 4 p = 99
11 p = 99
1 p = 99 ÷ 11 = 9
Number of girls who wear spectacles
= 3 p
= 3 x 9
= 27
Answer(s): 27
