Question 811304
Let {{{ 20 + x }}} = the man's age {{{ x }}} years from now
Let {{{ 5 + x }}} = the daughter's age {{{ x }}} years from now
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{{{ 20 + x = 2*( 5 + x ) }}}
{{{ 20 + x = 10 + 2x }}}
{{{ x = 10 }}}
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In 10 years the man's age is twice the daughter's age
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check:
{{{ 20 + x = 2*( 5 + x ) }}}
{{{ 20 + 10 = 2*( 5 + 10 ) }}}
{{{ 30 = 2*15 }}}
{{{ 30 = 30 }}}
OK