SOLUTION: There was an equal number of boys and girls in a school auditorium. After 24 boys left the auditorium, there were 3 times as many girls as boys. How many children were there in the

72



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Workout:



B = G           (1)

3(B-24) = G     (2)



Eq (1) allows us to substitute B for G on RHS of (2):

3(B-24) = B

2B = 72

B = 36  ==> G = 36  and  B+G=72





Check:  3(B-24) = 3(12) = 36 = G  (ok)