document.write( "Question 1204000: Ten years ago, Pepito's age was three times the age of his son, Chito. After ten years, Pepito’s age will be twice that of his son. Find the ratio of their present ages \n" ); document.write( "

Algebra.Com's Answer #839974 by greenestamps(13198) $\"\"$ $\"About$

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\n" ); document.write( "You have received two responses showing valid solutions using two variables.

\n" ); document.write( "Often the actual algebra required to solve the problem is easier if you can set the problem up using a single variable. Let's see what happens if we do that.

\n" ); document.write( "Let x = Chito's age 10 years ago
\n" ); document.write( "Then 3x = Pepito's age 10 years ago

\n" ); document.write( "Chito's age 10 years from now will be x+20; Pepito's age then will be 3x+20. At that time, Pepito's age will be twice Chito's age:

\n" ); document.write( " $\"3x%2B20=2%28x%2B20%29\"$
\n" ); document.write( " $\"3x%2B20=2x%2B40\"$
\n" ); document.write( " $\"x=20\"$

\n" ); document.write( "10 years ago, Chito's age was x=20 and Pepito's age was 3x=60.

\n" ); document.write( "So now their ages are x+10 = 30 and 3x+10 = 70.

\n" ); document.write( "ANSWER: the ratio of their ages is 30:70, or 3:7 (or 7:3)

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