There are 180 pupils in a parade square.
27 of the girls and
35 of the boys wear scarves, there are 116 pupils in the parade square who do not wear scarves. How many boys do not wear scarves?
| |
Girls |
Boys |
Total |
| Do not wear scarves |
5 u |
2 p |
116 |
| Wear scarves |
2 u |
3 p |
64 |
| Total |
7 u |
5 p |
180 |
Number of pupils who wear scarves
= 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 boys who do not wear scarves
= 2 p
= 2 x 8
= 16
Answer(s): 16
