Problema Solution
At a banquet, the ratio of the number of boys to the number of girls is 5:3. Halfway through the banquet, 45 boys leave and the ratio becomes 5:4. How many girls are at the banquet?
Answer provided by our tutors
Let
x = the number of boy
y = the number of girls
x : y = 5 : 3 cross-multiply
3x = 5y
45 boys leave and the ratio becomes 5:4 means
(x - 45) : y = 5 : 4 cross-multiply
4(x - 45) = 5y
We have the following system of equations:
3x = 5y
4(x - 45) = 5y
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x = 180 boys
y = 108 girls
There are 108 girls at the banquet.