Question 1091397
Find the total meters of fence needed
In words:
[ total cost ] / [ cost/meter ] = [ meters ]
{{{ 75000 / 100 = 750 }}} m
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Let the length = {{{ a }}}
Let the breadth = {{{ b }}}
(1) {{{ 2a + 2b = 750 }}}
(2) {{{ 11/4 = a/b }}}
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(2) {{{ 11b = 4a }}}
and
(1) {{{ 2a = 750 - 2b }}}
(1) {{{ a = (1/2)*( 750 - 2b ) }}}
Plug (1) into (2)
(2) {{{ 11b = 4*(1/2)*( 750 - 2b ) }}}
(2) {{{ 11b = 2*( 750 - 2b ) }}}
(2) {{{ 11b = 1500 - 4b }}}
(2) {{{ 15b = 1500 }}}
(2) {{{ b = 100 }}}
and
(1) {{{ a = (1/2)*(750 - 2b ) }}}
(1) {{{ a = (1/2)*( 750 - 200 ) }}}
(1) {{{ a = (1/2)*550 }}}
(1) {{{ a = 275 }}}
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The dimensions are 275 x 100 
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check:
Total length was {{{ 750 }}} m
(1) {{{ 2a + 2b = 750 }}}
(1) {{{ 2*275 + 2*100 = 750 }}}
(1) {{{ 550 + 200 = 750 }}}
(1) {{{ 750 = 750 }}}
and
(2) {{{ 11b = 4a }}}
(2) {{{ 11*100 = 4*275 }}}
(2) {{{ 1100 = 1100 }}}
OK