Question 1041878
Let {{{ a }}} = Andy's age now
Let {{{ b }}} = Andy's mother's age now
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(1) {{{ b = 9a }}}
(2) {{{ b + 3 = 5*( a + 3 ) }}}
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Substitute (1) into (2)
(2) {{{ 9a + 3 = 5*( a + 3 ) }}}
(2) {{{ 9a + 3 = 5a + 15 }}}
(2) {{{ 4a = 12 }}}
(2) {{{ a = 3 }}}
and
(1) {{{ b = 9a }}}
(1) {{{ b = 9*3 }}}
(1) {{{ b = 27 }}}
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Andy is 3 now
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check:
(2) {{{ b + 3 = 5*( a + 3 ) }}}
(2) {{{ 27 + 3 = 5*( 3 + 3 ) }}}
(2) {{{ 30 = 5*6 }}}
(2) {{{ 30 = 30 }}}