SOLUTION: 45% of the students in a class are girls and the number of boys exceeds the number of girls by 30. How many students are there in the class?

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Question 984761: 45% of the students in a class are girls and the number of boys exceeds the number of girls by 30. How many students are there in the class?
Found 2 solutions by Fombitz, vleith:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
B=G%2B30
G%2F%28G%2BB%29=45%2F100
Substituting,
100G=45%28G%2BG%2B30%29
100G=45%282G%2B30%29
100G=90G%2B1350
10G=1350
G=135
So then,
B=135%2B30
B=165

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
Let the total number of students be given by T
Let the number of girls be G and the number of boys be B
You are told
0.45T+=+G
You are also told G+%2B+30+=+B
You are asked to find T
G+%2B+B+=+T
G+%2B+%28G%2B30%29+=+T
2G+%2B+30+=+T
now substitute in for G
2%2A%280.45T%29+%2B+30+=+T
0.9T+%2B+30+=+T
30+=+0.1T
300+=+T
Thats a huge class.
There are 0.45+%2A+300+=+135 girls
There are 300+-+135+=+165 boys
SO there are 30 more boys that girls