SOLUTION: Total enrollment is 805 students. the ratio of girls to boy is 3 to 4. How many boys are enrolled

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Question 1148874: Total enrollment is 805 students. the ratio of girls to boy is 3 to 4. How many boys are enrolled
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52776) About Me  (Show Source):
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.

Let x be the number of boys.  Then the number of girls is 805-x.


    %28805-x%29%2Fx = 3%2F4


    4*(805-x) = 3x

    4*805 -4x = 3x

    4*805 = 3x + 4x

    4*805  = 7x

    x = %284%2A805%29%2F7 = 4*115 = 460.


ANSWER.  460 boys.


CHECK.   805-460%29%2F460 = 345%2F460 = %283%2A115%29%2F%284%2A115%29 = 3%2F4.    ! Correct !

Solved.




Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


Given that the ratio of girls to boys is 3 to 4, one standard way to start on solving the problem is to let the number of girls be 3x and the number of boys be 4x.

Then, since the total number of students is 805,

3x%2B4x+=+805
7x+=+805
x+=+115

The number of boys is 4x = 460.

An even shorter way to use the given ratio of 3 girls to 4 boys is to translate that into saying that 3/7 of the students are girls and 4/7 of them are boys. Then the answer is found with a single simple calculation:

number of boys = (4/7)*805 = 4*(805/7) = 4*115 = 460.