Question 1041651
Let {{{ n }}} = the number of correct answers
{{{ 75 - n }}} = the number of incorrect answers
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{{{ 5n - 2*( 75 - n ) = 165 }}}
{{{ 5n - 150 + 2n = 165 }}}
{{{ 7n = 315 }}}
{{{ n = 45 }}}
and
{{{ 75 - n = 30 }}}
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He answered 45 questions correctly
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check:
{{{ 5n - 2*( 75 - n ) = 165 }}}
{{{ 5*45 - 2*30 = 165 }}}
{{{ 225 - 60 = 165 }}}
{{{ 165 = 165 }}}
OK