SOLUTION: In Tae Kwon Do class, 40% of the students are boys. There are 18 fewer boys than girls. How many students are in the Tae Kwon Do class altogether?

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Question 1150617: In Tae Kwon Do class, 40% of the students are boys. There are 18 fewer boys than girls. How many students are in the Tae Kwon Do class altogether?
Found 2 solutions by VFBundy, ikleyn:
Answer by VFBundy(438) About Me  (Show Source):
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Number of girls = x
Number of boys = x - 18

%28x+-+18%29%2F%28x+%2B+%28x+-+18%29%29 = 0.4

%28x+-+18%29%2F%282x+-+18%29%29 = 0.4

Cross-multiply:

x - 18 = 0.4(2x - 18)

x - 18 = 0.8x - 7.2

0.2x = 10.8

x = 54

Number of girls = x = 54
Number of boys = x - 18 = 54 - 18 = 36

There are 54 girls in the class and 36 boys in the class. Therefore, there are 90 students in the class altogether.

Answer by ikleyn(52780) About Me  (Show Source):
You can put this solution on YOUR website!
.

Let x be the number of students in the class.


Then the number of girls is 0.6x, while the number of boys is 0.4x.


The difference is


    0.6x - 0.4x = 18, 

i.e.

    0.2x        = 18

       x        = 18/0.2 = 180/2 = 90.    ANSWER

Solved.