Question 1021100
Let {{{ a }}} = pounds of type A coffee used
{{{ 3a }}} = pounds of type B cofee
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{{{  4.1a + 5.2*3a = 689.5 }}}
{{{ 4.1a + 15.6a = 689.5 }}}
{{{ 19.7a = 689.5 }}}
{{{ a = 35 }}}
and
{{{ 3a = 105 }}}
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35 pounds of type A coffee are used
105 pounds of type B cofee are used