document.write( "Question 1201541: The average age of two sisters is three times the age of the younger one . in seven years' time the sum of their ages will be greater than the difference in their ages by 20 years. how old are they now? (The answer is 3 and 15)
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document.write( " so ,
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document.write( "Let x=older sister and y=younger sister
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document.write( "x+y=3y
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document.write( "7+(x+y) greater than (x-y)+20 \r
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document.write( "But how can you form Simultaneous equations from this ? How is it worked out ? \n" );
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Algebra.Com's Answer #835960 by Glaviolette(140)![]() ![]() You can put this solution on YOUR website! The average would be represented by (x+y)/2. This is equal to 3y. Then, their ages in 7 years would be x + 7 and y + 7. This sum is greater than the difference of their ages by 20 years. You don’t need to use a >. By adding the 20 to the difference, that is showing that the sum would be greater than the difference by 20.\r \n" ); document.write( "\n" ); document.write( " |