document.write( "Question 999488: At a local preschool there is a ratio of 3 boys to every 4 girls. If there are 245 kids enrolled, how many are boys? \n" ); document.write( "
Algebra.Com's Answer #617128 by addingup(3677)\"\" \"About 
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A ratio can be written in three different ways: 3 to 4, 3:4, and 3/4
\n" ); document.write( "What does this mean? It means that for every group of 7 students (3+4) there are 3 boys and 4 girls. And how many groups do we have? We have:
\n" ); document.write( "245/7= 35 We have 35 groups, and we just said that each group has 3 boys and 4 girls:
\n" ); document.write( "35*3= 105 boys
\n" ); document.write( "35*4= 140 girls
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\n" ); document.write( "Total: 245 students
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\n" ); document.write( "Here's how to set up an equation:
\n" ); document.write( "Let's call the number of girls x. Since the total is 245 students, 245-x= boys:
\n" ); document.write( "Set up the equation by writing the number of students in the ratio as a fraction:
\n" ); document.write( "3/4= (245-x)/x Cross multiply:
\n" ); document.write( "3x= 4(245-x) Multiply on right:
\n" ); document.write( "3x= 980-4x Add 4x on both sides:
\n" ); document.write( "7x= 980 Divide both sides by 7:
\n" ); document.write( "x= 140 this is how many girls there are. And:
\n" ); document.write( "245-140= 105= boys
\n" ); document.write( "As you see, we got the same answers.
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\n" ); document.write( "Now you can teach the class ;-)
\n" ); document.write( "Good luck,
\n" ); document.write( "J \n" ); document.write( "
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