There are 117 pupils in a basketball court.
38 of the boys and
47 of the girls wear glasses, there are 69 pupils in the basketball court who do not wear glasses. How many girls wear glasses?
| |
Boys |
Girls |
Total |
| Do not wear glasses |
5 u |
3 p |
69 |
| Wear glasses |
3 u |
4 p |
48 |
| Total |
8 u |
7 p |
117 |
Number of pupils who wear glasses
= 117 - 69
= 48
5 u + 3 p = 69 --- (1)
3 u + 4 p = 48 --- (2)
Make u the same.
(1)
x 3 15 u + 9 p = 207 --- (3)
(2)
x 5 15 u + 20 p = 240 --- (4)
(4) - (3)
(15 u + 20 p) - (15 u + 9 p) = 240 - 207
20 p - 9 p = 33
11 p = 33
1 p = 33 ÷ 11 = 3
Number of girls who wear glasses
= 4 p
= 4 x 3
= 12
Answer(s): 12
