Question 194578
Let {{{p}}}= the number of plastic cups sold
Let {{{c}}}= the number of ceramic cups sold
given:
(1) {{{p + c = 400}}}
(2) {{{3.5p + 4c = 1458}}}
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Multiply both sids of (1) by {{{3.5}}} and
subtract from (2)
{{{3.5p + 4c = 1458}}}
{{{-3.5p - 3.5c = -1400}}}
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{{{.5c = 58}}}
{{{c = 116}}}
and
(1) {{{p + c = 400}}}
{{{p + 116 = 400}}}
{{{p = 284}}}
116 ceramic cups and 284 plastic cups were sold
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(2) {{{3.5p + 4c = 1458}}}
{{{3.5*284 + 4*116 = 1458}}}
{{{994 + 464 = 1458}}}
The value of the plastic cups sold was $994
The value of the ceramic cups sold was $464