There are 180 children in a school field.
27 of the boys and
35 of the girls wear glasses, there are 116 children in the school field who do not wear glasses. How many girls do not wear glasses?
| |
Boys |
Girls |
Total |
| Do not wear glasses |
5 u |
2 p |
116 |
| Wear glasses |
2 u |
3 p |
64 |
| Total |
7 u |
5 p |
180 |
Number of children who wear glasses
= 180 - 116
= 64
5 u + 2 p = 116 --- (1)
2 u + 3 p = 64 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 232 --- (3)
(2)
x 5 10 u + 15 p = 320 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 320 - 232
15 p - 4 p = 88
11 p = 88
1 p = 88 ÷ 11 = 8
Number of girls who do not wear glasses
= 2 p
= 2 x 8
= 16
Answer(s): 16
