There are 99 children in a hall.
27 of the boys and
35 of the girls wear hats, there are 66 children in the hall who do not wear hats. How many girls wear hats?
| |
Boys |
Girls |
Total |
| Do not wear hats |
5 u |
2 p |
66 |
| Wear hats |
2 u |
3 p |
33 |
| Total |
7 u |
5 p |
99 |
Number of children who wear hats
= 99 - 66
= 33
5 u + 2 p = 66 --- (1)
2 u + 3 p = 33 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 132 --- (3)
(2)
x 5 10 u + 15 p = 165 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 165 - 132
15 p - 4 p = 33
11 p = 33
1 p = 33 ÷ 11 = 3
Number of girls who wear hats
= 3 p
= 3 x 3
= 9
Answer(s): 9
