264 children are in a school.
14 of the girls and
18 of the boys wear glasses.
44 children wear glasses.
- How many girls are there?
- How many boys are there?
- How many children do not wear glasses?
|
Number |
Girls |
Boys |
Total |
264 |
4 u |
8 p |
Wear glasses |
44 |
1 u |
1 p |
No glasses |
|
3 u |
7 p |
(a)
Number of girls = 4 u
Number of boys = 8 p
4 u + 8 p = 264 --- (1)
1 u + 1 p = 44 --- (2)
(2)
x 4 4 u + 4 p = 176 --- (3)
(1) - (3)
(4 u + 8 p) - (4 u + 4 p) = 264 - 176
4 u + 8 p - 4 u - 4 p = 88
4 p = 88
1 p = 88 ÷ 4 = 22
Substitute 1 p = 22 into (2).
1 u + 1 p = 44
1 u + 22 = 44
1 u = 44 - 22 = 22
Number of girls
= 4 u
= 4 x 22
= 88
(b)
Number of boys
= 8 p
= 8 x 22
= 176
(c)
Number of girls who do not wear glasses
= 4 u - 1 u
= 3 u
Number of boys who do not wear glasses
= 8 p - 1 p
= 7 p
Number of children who do not wear glasses
= 264 - 44
= 220
Answer(s): (a) 88; (b) 176; (c) 220