document.write( "Question 860348: Please help me solve this equation.
\n" ); document.write( "Find my age, my grandmother's age and my sister's age if:
\n" ); document.write( "My father is 40 and he is four years older than my mother
\n" ); document.write( "My mother is three times more than my age.
\n" ); document.write( "And my sister is 75% my age and 15% of my grandmother's age
\n" ); document.write( "Answers:
\n" ); document.write( "My age = 40-4/3= 12 years old
\n" ); document.write( "My sister's age = 75% of 12 = 9 + 15% of grandmother's age
\n" ); document.write( " \n" ); document.write( "
Algebra.Com's Answer #518350 by rothauserc(4718)\"\" \"About 
You can put this solution on YOUR website!
let x be your mother's age
\n" ); document.write( "40 = x + 4
\n" ); document.write( "let y be your age
\n" ); document.write( "x = 3y
\n" ); document.write( "solve first equation for x
\n" ); document.write( "x = 36
\n" ); document.write( "substitute for x in second equation
\n" ); document.write( "36 = 3y
\n" ); document.write( "3y = 36
\n" ); document.write( "y = 12
\n" ); document.write( "you are 12 years old
\n" ); document.write( "your sister is .75 * 12 = 9 years old
\n" ); document.write( "let z be your grandmother's age
\n" ); document.write( ".15 * z = 9
\n" ); document.write( "z = 9 / .15 = 60
\n" ); document.write( "your grandmother is 60 years old\r
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