176 people are in a school.
14 of the males and
18 of the females wear glasses.
26 people wear glasses.
- How many males are there?
- How many females are there?
- How many people do not wear glasses?
|
Number |
Males |
Females |
Total |
176 |
4 u |
8 p |
Wear glasses |
26 |
1 u |
1 p |
No glasses |
|
3 u |
7 p |
(a)
Number of males = 4 u
Number of females = 8 p
4 u + 8 p = 176 --- (1)
1 u + 1 p = 26 --- (2)
(2)
x 4 4 u + 4 p = 104 --- (3)
(1) - (3)
(4 u + 8 p) - (4 u + 4 p) = 176 - 104
4 u + 8 p - 4 u - 4 p = 72
4 p = 72
1 p = 72 ÷ 4 = 18
Substitute 1 p = 18 into (2).
1 u + 1 p = 26
1 u + 18 = 26
1 u = 26 - 18 = 8
Number of males
= 4 u
= 4 x 8
= 32
(b)
Number of females
= 8 p
= 8 x 18
= 144
(c)
Number of males who do not wear glasses
= 4 u - 1 u
= 3 u
Number of females who do not wear glasses
= 8 p - 1 p
= 7 p
Number of people who do not wear glasses
= 176 - 26
= 150
Answer(s): (a) 32; (b) 144; (c) 150