Question 890422
Let {{{ b }}} = the number of benches
Let {{{ s }}} = the number of students
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(1) {{{ s / 3 = b + 1/3 }}}
(2) {{{ b = s/4 + 1 }}}
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(1) {{{ s = 3b + 1 }}}
(2) {{{ 4b = s + 4  }}}
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(1) {{{ s - 3b = 1 }}}
(2) {{{ -s + 4b = 4 }}}
Add the equations
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{{{ b = 5 }}}
and
(1) {{{ s = 3*5 + 1 }}}
(1) {{{ s = 16 }}}
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There are 16 students and 5 benches
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check:
( 3 students )x( 5 benches ) = ( 15 students ) + ( 1 extra student )
and
( 16 students ) / ( 4 students per bench ) = ( 5 benches ) - ( 1 extra bench )
Hope this helps