document.write( "Question 1028269: One son, one mother, one father, total age is 100yrs ,, son is half age of mother,, and mother is -5yrs of father.. Pls help me to calculate the age of son,,,,, the age of mother,,,,, the age of father \n" ); document.write( "

Algebra.Com's Answer #643377 by fractalier(6550) $\"\"$ $\"About$

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Call their ages s, m, and f. Then we have
\n" ); document.write( "s + m + f = 100
\n" ); document.write( "s = (1/2)m
\n" ); document.write( "m = f - 5 (or f = m + 5)
\n" ); document.write( "Now substitute into the first equation and get
\n" ); document.write( "(1/2)m + m + m+5 = 100
\n" ); document.write( "(5/2)m + 5 = 100
\n" ); document.write( "(5/2)m = 95
\n" ); document.write( "m = 38
\n" ); document.write( "That means
\n" ); document.write( "s = 19 and
\n" ); document.write( "f = 43
\n" ); document.write( " \n" ); document.write( "

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