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若1D班有42名學生,男生人數比女生人數多1/3,問男生和女生各有多少人?
設女生有x人,男生有(x+1/3x).
42=(x+1/3x)+x
42=7/3x
42*3/7=x
x=18
所以女生有18人,
男生有:
18+18(1/3)
=24
即男生有24人

設女生人數是x
男生人數是x+1/3
x+x+1/3=42
2x+1/3=42
6x+1=126
6x=125
x=125/6
男生人數是127/6 女生人數是125/6

男生有:
42/2*1/3+42/2
=7+21
=28(人)
女生有：
42-28
=14(人)

Let x be the number of girls

Therefore the number of boys should be (x + 1/3x)

(x + 1/3x) + x = 42

2x + 1/3 x = 42

(6x + x)/3 = 42

7x = 126

x = 18

The number of girls is 18 and

the number of boys is 24.

Let x and 4/3x be the number of girls and boys in the class respectively
x+4/3x=42
(1+4/3)x=42
7/3x=42
x=42*3/7
x=18
Therefore, there are 18 girls and 24 boys in the class

let x be the number of girls

(x+1/3x)+x=42
2x+1/3x=42
x=18

the number of boys
=42-18
=34

2006-12-07 22:46:07 補充：
the number of boys=42-18=24

let no. of girls is X
no. of boys is (1 1/3)X
X+4X/3=42
7X/3=42
X=18
So, there are 18 girls and 24 boys

設女生人數是x,
x+x+1/3x=42
2x+1/3x=42
2又1/3x=42
x=18
女生人數是18人,
男生人數=42-18=24人