179 people are in a school.
14 of the males and
17 of the females wear glasses.
44 people wear glasses.
- How many males are there?
- How many females are there?
- How many people do not wear glasses?
|
Number |
Males |
Females |
Total |
179 |
4 u |
7 p |
Wear glasses |
44 |
1 u |
1 p |
No glasses |
|
3 u |
6 p |
(a)
Number of males = 4 u
Number of females = 7 p
4 u + 7 p = 179 --- (1)
1 u + 1 p = 44 --- (2)
(2)
x 4 4 u + 4 p = 176 --- (3)
(1) - (3)
(4 u + 7 p) - (4 u + 4 p) = 179 - 176
4 u + 7 p - 4 u - 4 p = 3
3 p = 3
1 p = 3 ÷ 3 = 1
Substitute 1 p = 1 into (2).
1 u + 1 p = 44
1 u + 1 = 44
1 u = 44 - 1 = 43
Number of males
= 4 u
= 4 x 43
= 172
(b)
Number of females
= 7 p
= 7 x 1
= 7
(c)
Number of males who do not wear glasses
= 4 u - 1 u
= 3 u
Number of females who do not wear glasses
= 7 p - 1 p
= 6 p
Number of people who do not wear glasses
= 179 - 44
= 135
Answer(s): (a) 172; (b) 7; (c) 135