Question 401518
Let {{{p}}} = dozens of peanut butter cookies sold
Let {{{c}}} = dozens of chocolate chip cookies sold
given:
(1) {{{p = c + 85}}}
(2) {{{650p + 900c = 405550}}}
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Substitute (1) into (2)
{{{650*(c + 85) + 900c = 405550}}}
{{{650c + 55250 + 900c = 405550}}}
{{{1550c = 350300}}}
{{{c = 226}}}
and, from (1)
{{{p = 226 + 85}}}
{{{p = 311}}}
311 dozen peanut butter cookies were sold
226 dozen chocolate chip cookies were sold
check answer:
(2) {{{650p + 900c = 405550}}}
{{{650*311 + 900*226 = 405550}}}
{{{202150 + 203400 = 405550}}}
{{{405550 = 405550}}}
OK