Question 1103435
Let {{{ x }}} = the original number of children
{{{ (1/3)*x }}} = the original number of boys
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{{{ (1/3)*x - 20 = (1/4)*( x - 20 ) }}}
{{{ (1/3)*x - 20 = (1/4)*x - 5 }}}
{{{ (1/3)*x - (1/4)*x = 15 }}}
{{{ (4/12)*x - (3/12)*x = 15 }}}
{{{ (1/12)*x = 15 }}}
{{{ x = 180 }}}
There were 180 children at first
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check:
1/3 were boys, so {{{ 180/3 = 60 }}} were boys
20 left, leaving 40 boys
The total number of children was then {{{ 180 - 20 = 160 }}}
{{{ 40 = (1/4)*160 }}}
{{{ 40 = 40 }}}
OK
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