150 people are in a school.
14 of the females and
16 of the males wear glasses.
26 people wear glasses.
- How many females are there?
- How many males are there?
- How many people do not wear glasses?
|
Number |
Females |
Males |
Total |
150 |
4 u |
6 p |
Wear glasses |
26 |
1 u |
1 p |
No glasses |
|
3 u |
5 p |
(a)
Number of females = 4 u
Number of males = 6 p
4 u + 6 p = 150 --- (1)
1 u + 1 p = 26 --- (2)
(2)
x 4 4 u + 4 p = 104 --- (3)
(1) - (3)
(4 u + 6 p) - (4 u + 4 p) = 150 - 104
4 u + 6 p - 4 u - 4 p = 46
2 p = 46
1 p = 46 ÷ 2 = 23
Substitute 1 p = 23 into (2).
1 u + 1 p = 26
1 u + 23 = 26
1 u = 26 - 23 = 3
Number of females
= 4 u
= 4 x 3
= 12
(b)
Number of males
= 6 p
= 6 x 23
= 138
(c)
Number of females who do not wear glasses
= 4 u - 1 u
= 3 u
Number of males who do not wear glasses
= 6 p - 1 p
= 5 p
Number of people who do not wear glasses
= 150 - 26
= 124
Answer(s): (a) 12; (b) 138; (c) 124