SOLUTION: Suppose the ratio of girls and boys in your school is 19:17. There are 1908 students altogether. a.Solve the proportion g/b=19/17 for g. b.Write and solve the system of equations

Solution


Part a.


Cross-multiply


Divide by 17


Part b.
We are given that the total number of students is 1908, and given the
presumption that all students have to be either boys or girls we can say:


From part a. we have  which can be written:


Giving us a system of equations:
Eq. 1) 
Eq. 2) 

Solve
Step 1: Multiply equation 1 by 19 resulting in equation 3
Eq. 3) 

Add equation 2 to equation 3, term by term, resulting in equation 4
Eq. 3) 
Eq. 2) 

Eq. 4) 

Divide equation 4 by 36:


Knowing that there are 1007 girls, we can calculate the number of boys by:





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