160 adults are in a school.
14 of the men and
17 of the women wear glasses.
34 adults wear glasses.
- How many men are there?
- How many women are there?
- How many adults do not wear glasses?
|
Number |
Men |
Women |
Total |
160 |
4 u |
7 p |
Wear glasses |
34 |
1 u |
1 p |
No glasses |
|
3 u |
6 p |
(a)
Number of men = 4 u
Number of women = 7 p
4 u + 7 p = 160 --- (1)
1 u + 1 p = 34 --- (2)
(2)
x 4 4 u + 4 p = 136 --- (3)
(1) - (3)
(4 u + 7 p) - (4 u + 4 p) = 160 - 136
4 u + 7 p - 4 u - 4 p = 24
3 p = 24
1 p = 24 ÷ 3 = 8
Substitute 1 p = 8 into (2).
1 u + 1 p = 34
1 u + 8 = 34
1 u = 34 - 8 = 26
Number of men
= 4 u
= 4 x 26
= 104
(b)
Number of women
= 7 p
= 7 x 8
= 56
(c)
Number of men who do not wear glasses
= 4 u - 1 u
= 3 u
Number of women who do not wear glasses
= 7 p - 1 p
= 6 p
Number of adults who do not wear glasses
= 160 - 34
= 126
Answer(s): (a) 104; (b) 56; (c) 126