Question 1088579
Let {{{ a }}} = Isabel's age now
Let {{{ b }}} = Marie's age now
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(1) {{{ a = b + 10 }}}
(2) {{{ 2*( a + 2 ) = 3*( b + 2 ) }}}
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Substitute (1) into (2)
(2) {{{ 2*( b + 10 + 2 ) = 3*( b + 2 ) }}}
(2) {{{ 2*( b + 12 ) = 3*( b + 2 ) }}}
(2) {{{ 2b + 24 = 3b + 6 }}}
(2) {{{ b = 24 - 6 }}}
(2) {{{ b = 18 }}}
and
(1) {{{ a = 18 + 10 }}}
(1) {{{ a = 28 }}}
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Isabel is 28
Marie is 18
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check:
(2) {{{ 2*( a + 2 ) = 3*( b + 2 ) }}}
(2) {{{ 2*( 28 + 2 ) = 3*( 18 + 2 ) }}}
(2) {{{ 2*30 = 3*20 }}}
(2) {{{ 60 = 60 }}}
OK