Stephanie M. answered 05/02/15
Tutor
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Degree in Math with 5+ Years of Tutoring Experience
Let's write a system of equations to model this questions.
VARIABLES
n = New South Wales students
v = Victoria students
t = Tasmania students
q = Queensland students
EQUATIONS
n = v + 4 (New South Wales has 4 more students than Victoria)
q = 1/2n (Queensland has 1/2 the number from New South Wales)
t = 1/3v (Tasmania has 1/3 the number from Victoria)
q + v = t + n (Queensland and Victoria have the same number as Tasmania and New South Wales)
Now, let's make some substitutions. We'll rearrange the first three equations to try to find expressions for q, v, and t in terms of n.
n = v + 4
v = n - 4
q = 1/2n
t = 1/3v
t = 1/3(n - 4)
t = 1/3n - 4/3
Substitute those values into the fourth equation and solve for n:
q + v = t + n
1/2n + n - 4 = 1/3n - 4/3 + n
3/2n - 4 = 4/3n - 4/3
3/2n - 4/3n = -4/3 + 4
9/6n - 8/6n = -4/3 + 12/3
1/6n = 8/3
n = 6(8/3)
n = 16
The number of students from New South Wales is 16. Substitute that value back into the other equations to get:
v = n - 4
v = 16 - 4
v = 12
q = 1/2n
q = 1/2n
q = 1/2(16)
q = 8
t = 1/3(n - 4)
t = 1/3(16 - 4)
t = 1/3(12)
t = 4
There will be 12 students from Victoria, 8 students from Queensland, and 4 students from Tasmania.