Question 1147791
Let {{{ x }}} = Mary's age now
{{{ 2x }}} = Pete's age now
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{{{ ( x - 7 ) + ( 2x - 7 ) = 31 }}}
{{{ x - 7 + 2x - 7 = 31 }}}
{{{ 3x = 31 + 14 }}}
{{{ 3x = 45 }}}
{{{ x = 15 }}}
and
{{{ 2x = 30 }}}
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Mary is 15
Pete is 30
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Check:
7 yrs ago the sum of their ages was:
{{{ 15 + 30 - 7 - 7 = 31 }}}
OK