There are 116 pupils in a hall.
38 of the boys and
47 of the girls wear scarves, there are 67 pupils in the hall who do not wear scarves. How many girls wear scarves?
| |
Boys |
Girls |
Total |
| Do not wear scarves |
5 u |
3 p |
67 |
| Wear scarves |
3 u |
4 p |
49 |
| Total |
8 u |
7 p |
116 |
Number of pupils who wear scarves
= 116 - 67
= 49
5 u + 3 p = 67 --- (1)
3 u + 4 p = 49 --- (2)
Make u the same.
(1)
x 3 15 u + 9 p = 201 --- (3)
(2)
x 5 15 u + 20 p = 245 --- (4)
(4) - (3)
(15 u + 20 p) - (15 u + 9 p) = 245 - 201
20 p - 9 p = 44
11 p = 44
1 p = 44 ÷ 11 = 4
Number of girls who wear scarves
= 4 p
= 4 x 4
= 16
Answer(s): 16
