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Answer:
Step-by-step explanation:
The total number of students (32) corresponds to the total number of ratio units (3+5 = 8), so each ratio unit represents 32/8 = 4 students.
The 3 ratio units representing boys will stand for 3×4 = 12 boys.
The 5 ratio units representing girls will stand for 5×4 = 20 girls.
There are 12 boys and 20 girls in Janice's classroom.
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<em>Additional comment</em>
I find the above solution to be the easiest.
You can also write a system of equations. Let b and g represent the numbers of boys and girls, respectively.
b/g = 3/5
b +g = 32
Multiplying the first equation by g gives an expression for b that can be substituted into the second equation:
b = (3/5)g
(3/5)g +g = 32
8/5g = 32 . . . . . . . . . . . . . . . . . collect terms
g = (5/8)(32) = 5·4 = 20 . . . . . . multiply by 5/8
b = (3/5)(20) = 3·4 = 12 . . . . . . . find b using the value of g
