There are 156 pupils in a basketball court.
27 of the girls and
35 of the boys wear glasses, there are 102 pupils in the basketball court who do not wear glasses. How many boys wear glasses?
| |
Girls |
Boys |
Total |
| Do not wear glasses |
5 u |
2 p |
102 |
| Wear glasses |
2 u |
3 p |
54 |
| Total |
7 u |
5 p |
156 |
Number of pupils who wear glasses
= 156 - 102
= 54
5 u + 2 p = 102 --- (1)
2 u + 3 p = 54 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 204 --- (3)
(2)
x 5 10 u + 15 p = 270 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 270 - 204
15 p - 4 p = 66
11 p = 66
1 p = 66 ÷ 11 = 6
Number of boys who wear glasses
= 3 p
= 3 x 6
= 18
Answer(s): 18
