Question 799776
Let {{{ c }}} = cost of the cat
Let {{{ d }}} = cost of the dog
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(1) {{{ c = (1/3)*d }}}
(2) {{{ c + d = 220 }}}
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(1) {{{ d = 3c }}}
by substitution:
(2) {{{ c + 3c = 220 }}}
(2) {{{ 4c = 220 }}}
(2) {{{ c = 55 }}}
and
(1) {{{ d = 3*55 }}}
(1) {{{ d = 165 }}}
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The cat costs $55
The dog costs $165