Question 1037776
Cindy becomes {{{ 20 }}} yrs old
{{{ 20 - m }}} yrs from now
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John will be {{{ 30 + 20 - m }}} at that time
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check:
suppose {{{ m = 15 }}}
Cindy will be {{{ 20 }}} in {{{ 5 }}} yrs
John will be {{{ 35 }}} in {{{ 5 }}} yrs
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{{{ 30 + 20 - m = 30 + 20 -15 }}}
{{{ 30 + 20 - m = 35 }}}
OK