There are 176 students in a parade square.
38 of the girls and
47 of the boys wear hats, there are 99 students in the parade square who do not wear hats. How many boys wear hats?
| |
Girls |
Boys |
Total |
| Do not wear hats |
5 u |
3 p |
99 |
| Wear hats |
3 u |
4 p |
77 |
| Total |
8 u |
7 p |
176 |
Number of students who wear hats
= 176 - 99
= 77
5 u + 3 p = 99 --- (1)
3 u + 4 p = 77 --- (2)
Make u the same.
(1)
x 3 15 u + 9 p = 297 --- (3)
(2)
x 5 15 u + 20 p = 385 --- (4)
(4) - (3)
(15 u + 20 p) - (15 u + 9 p) = 385 - 297
20 p - 9 p = 88
11 p = 88
1 p = 88 ÷ 11 = 8
Number of boys who wear hats
= 4 p
= 4 x 8
= 32
Answer(s): 32
