maths questions??(3)
2006-11-27 1:06 am
2.)The number of student in school A is 75% of that in school B.If the two schools have 2800 altogether,find the difference of the number between the schools.
回答 (3)
2006-11-27 1:18 am
✔ 最佳答案
let the number of student in school B be x75%x+x=2800
75/100+x=2800
175/100x=2088
x=2800(100/175)
x=1600
1600-1600(75%)
=1600-1200
=400
the difference of the number the school is 400
參考: me
2006-11-27 1:12 am
Let the number of students in school A and B are a and b respectively.
a=0.75b........(1)
a+b=2800.....(2)
Sub (1) into (2),
0.75b+b=2800
1.75b=2800
b= 1600
and thus a = 0.75b = 0.75(1600) = 1200
The difference of the number between the schools = b-a = 1600-1200 =400.
a=0.75b........(1)
a+b=2800.....(2)
Sub (1) into (2),
0.75b+b=2800
1.75b=2800
b= 1600
and thus a = 0.75b = 0.75(1600) = 1200
The difference of the number between the schools = b-a = 1600-1200 =400.
2006-11-27 1:10 am
Let the no. of student in school B is k
Therefore,the no. of student in school A is 0.75k
k+0.75k=2800
1.75k=2800
k=1600
so, the no. of student in school B is 1600
and, the no. of student in school A is 1200
difference of the number between the schools is 1600-1200=400
Therefore,the no. of student in school A is 0.75k
k+0.75k=2800
1.75k=2800
k=1600
so, the no. of student in school B is 1600
and, the no. of student in school A is 1200
difference of the number between the schools is 1600-1200=400
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