Question 1073457
Let {{{ a }}} = number of $5 bills
Let {{{ b }}} = number of $10 bills
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(1) {{{ a + b = 28 }}}
(2) {{{ 5a + 10b = 230 }}}
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(2) {{{ a + 2b = 46 }}}
Subtract (1) from (2)
(2) {{{ a + 2b = 46 }}}
(1) {{{ -a - b = -28 }}}
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{{{ b = 18 }}}
and
(1) {{{ a + b = 28 }}}
(1) {{{ a + 18 = 28 }}}
(1) {{{ a = 10 }}}
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There are 10 $5 bills
There are 18 $10 bills
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check:
(2) {{{ 5a + 10b = 230 }}}
(2) {{{ 5*10 + 10*18 = 230 }}}
(2) {{{ 50 + 180 = 230 }}}
(2) {{{ 230 = 230 }}}
OK