Question 1153677
Let {{{ a }}} = Aunt S's age
Let {{{ b }}} = Fred's age
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(1) {{{ a = 3b }}}
(2) {{{ a + b = 48 }}}
Substitute (1) into (2)
(2) {{{ 3b + b = 48 }}}
(2) {{{ 4b = 48 }}}
(2) {{{ b = 12 }}}
Plug this result back into (2)
(2) {{{ a + b = 48 }}}
(2) {{{ a + 12 = 48 }}}
(2) {{{ a = 36 }}}
Aunt Samantha is 36
Fred is 12