There are 115 students in a tuckshop.
38 of the girls and
47 of the boys wear scarves, there are 65 students in the tuckshop who do not wear scarves. How many boys do not wear scarves?
| |
Girls |
Boys |
Total |
| Do not wear scarves |
5 u |
3 p |
65 |
| Wear scarves |
3 u |
4 p |
50 |
| Total |
8 u |
7 p |
115 |
Number of students who wear scarves
= 115 - 65
= 50
5 u + 3 p = 65 --- (1)
3 u + 4 p = 50 --- (2)
Make u the same.
(1)
x 3 15 u + 9 p = 195 --- (3)
(2)
x 5 15 u + 20 p = 250 --- (4)
(4) - (3)
(15 u + 20 p) - (15 u + 9 p) = 250 - 195
20 p - 9 p = 55
11 p = 55
1 p = 55 ÷ 11 = 5
Number of boys who do not wear scarves
= 3 p
= 3 x 5
= 15
Answer(s): 15
