There are 175 students in a basketball court.
38 of the girls and
47 of the boys wear glasses, there are 97 students in the basketball court who do not wear glasses. How many boys wear glasses?
| |
Girls |
Boys |
Total |
| Do not wear glasses |
5 u |
3 p |
97 |
| Wear glasses |
3 u |
4 p |
78 |
| Total |
8 u |
7 p |
175 |
Number of students who wear glasses
= 175 - 97
= 78
5 u + 3 p = 97 --- (1)
3 u + 4 p = 78 --- (2)
Make u the same.
(1)
x 3 15 u + 9 p = 291 --- (3)
(2)
x 5 15 u + 20 p = 390 --- (4)
(4) - (3)
(15 u + 20 p) - (15 u + 9 p) = 390 - 291
20 p - 9 p = 99
11 p = 99
1 p = 99 ÷ 11 = 9
Number of boys who wear glasses
= 4 p
= 4 x 9
= 36
Answer(s): 36
