
Ryan D.
asked 08/29/17Girl bet me i couldnt find the awnser to this math problem
The number of pupils in school A is equal to half the number of pupils in school B. The ratio of the boys in school A and the boys in school B is 1:3 and the ratio of the girls in school A and the girls in school B is 3:5. The number of boys in school B is 200 higher than the number of boys in school A. Find the number of boys and girls in each school.
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1 Expert Answer

Andy C. answered 08/29/17
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Math/Physics Tutor
Xa = # of boys in school A
Xb = # of boys in school B
Ya = # of girls in school A
Yb = # of girls in school B
There are half as many students in school A as in school B:
(Xa + Ya )*2 = Xb + Yb
2*Xa + 2*Ya = Xb + Yb <--- equation #1
The ratio of boys between school A and School B is 1 to 3.
Xa + 3*Xb = Xa + Xb
3*Xb = Xb
2*Xb = 0
Xb = 0 <--- equation #2
The ratio of girls between school A and School B is 3 to 5.
3*Ya + 5*Yb = Ya + Yb
2*Ya + 4 * Yb = 0
Ya + 2*Yb = 0
Ya = -2*Yb <--- equation #3
There are 200 more boys in school B than in school A.
Xa + 200 = Xb <--- equation #4
Since Xb=0 per equation #2, Xa + 200 = 0
Xa = -200
Substituting these values into equation #1:
2*(-200) + 2*Ya = 0 + Yb
2*Ya - 400 = Yb <--- call this equation ALPHA.
Substituting equation #3 into equation ALPHA:
2*(-2*Yb) - 400 = Yb
-4*Yb - 400 = Yb
-400 = 5*Yb
Yb = -80
Ya = -2*-80 = 160
There are -200 boys in school A
There are zero boys in school B
There are 160 girls in school A
There are -80 girls in school B.
School A has -200 + 160 = -40 students
School B has 0 + -80 students.
So yes there are half as many students in school A as in school B since half of -80 is -40.
There are -200 total boys.
The ratio of boys between the two schools is -200/-200 = 1 and 0/200 = 0
So yes, 1*-200 + 3 * 0 = -200 + 0 = -200 which is the 3 to 1 ratio.
There are 80 total girls.
The ratio of girls between the two schools is 160/80 = 2 and -80/80 = -1.
So yes, 3*160 + 5*-80 = 480 - 400 = 80 which is the 3 to 5 ratio.
I do believe she owes you some money
because this problem is SO FLAWED!
Perhaps call the bet off, and declare it NULL and VOID
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Kenneth S.
08/29/17