There are 149 students in a tuckshop.
27 of the boys and
35 of the girls wear watches, there are 97 students in the tuckshop who do not wear watches. How many girls do not wear watches?
| |
Boys |
Girls |
Total |
| Do not wear watches |
5 u |
2 p |
97 |
| Wear watches |
2 u |
3 p |
52 |
| Total |
7 u |
5 p |
149 |
Number of students who wear watches
= 149 - 97
= 52
5 u + 2 p = 97 --- (1)
2 u + 3 p = 52 --- (2)
Make u the same.
(1)
x 2 10 u + 4 p = 194 --- (3)
(2)
x 5 10 u + 15 p = 260 --- (4)
(4) - (3)
(10 u + 15 p) - (10 u + 4 p) = 260 - 194
15 p - 4 p = 66
11 p = 66
1 p = 66 ÷ 11 = 6
Number of girls who do not wear watches
= 2 p
= 2 x 6
= 12
Answer(s): 12
