There are 126 children in a parade square.
27 of the boys and
35 of the girls wear glasses, there are 79 children in the parade square who do not wear glasses. How many girls wear glasses?
| |
Boys |
Girls |
Total |
| Do not wear glasses |
5 u |
2 p |
79 |
| Wear glasses |
2 u |
3 p |
47 |
| Total |
7 u |
5 p |
126 |
Number of children who wear glasses
= 126 - 79
= 47
5 u + 2 p = 79 --- (1)
2 u + 3 p = 47 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 158 --- (3)
(2)
x 5 10 u + 15 p = 235 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 235 - 158
15 p - 4 p = 77
11 p = 77
1 p = 77 ÷ 11 = 7
Number of girls who wear glasses
= 3 p
= 3 x 7
= 21
Answer(s): 21
