Question 1047653
Let {{{ a }}} = Kathy's age now
Let {{{ b }}} = her cat's age now
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(1) {{{ a = b + 6 }}}
(2) {{{ a + 1 = 2*( b + 1 ) }}}
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(2) {{{ a + 1 = 2b + 2 }}}
Substitute (1) into (2)
(2) {{{ b + 6 + 1 = 2b + 2 }}}
(2) {{{ b + 7 = 2b + 2 }}}
(2) {{{ b = 5 }}}
and
(1) {{{ a = b + 6 }}}
(1) {{{ a = 5 + 6 }}}
(1) {{{ a = 11 }}}
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Kathy is 11 now
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check:
(2) {{{ a + 1 = 2*( b + 1 ) }}}
(2) {{{ 11 + 1 = 2*( 5 + 1 ) }}}
(2) {{{ 12 = 2*6 }}}
(2) {{{ 12 = 12 }}}
OK