Question 1135386
Let {{{ a }}} = the cost of 1 scone
Let {{{ b }}} = the cost of 1 lg coffee
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(1) {{{ 7a + 2b = 22.3 }}}
(2) {{{ 4a + 5b = 20.38 }}}
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Multiply both sides of (1) by {{{ 5 }}}
Multiply both sides of (2) by {{{ 2 }}}
Subtract (2) from (1)
(1) {{{ 35a + 10b = 111.5 }}}
(2) {{{ -8a - 10b = -40.76 }}}
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{{{ 27a = 70.74 }}}
{{{ a = 2.62 }}}
and
(1) {{{ 4a + 5b = 20.38 }}}
(1) {{{ 4*2.62 + 5b = 20.38 }}}
(1) {{{ 10.48 + 5b = 20.38 }}}
(1) {{{ 5b = 9.9 }}}
(1) {{{ b = 1.98 }}}
One large coffee costs $1.98
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(1) {{{ 4*2.62 + 5*1.98 = 20.38 }}}
(1) {{{ 10.48 + 9.9 = 20.38 }}}
(1) {{{ 20.38 = 20.38 }}}
Ok
You can check (2)