Question 1051294
Let {{{ a }}} = Juan's age now
Let {{{ b }}} = Jan's age now
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(1) {{{ a = 4b }}}
(2) {{{ a + 12 = 6*( b - 3 ) }}}
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(2) {{{ a + 12 = 6b - 18 }}}
(2) {{{ a = 6b - 30 }}}
Plug (1) into (2)
(2) {{{ 4b = 6b - 30 }}}
(2) {{{ 2b = 30 }}}
(2) {{{ b = 15 }}}
and
(1) {{{ a = 4b }}}
(1) {{{ a = 4*15 }}}
(1) {{{ a = 60 }}}
Juan is 60
jan is 15
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check:
(2) {{{ a + 12 = 6*( b - 3 ) }}}
(2) {{{ 60 + 12 = 6*( 15 - 3 ) }}}
(2) {{{ 72 = 6*12 }}}
(2) {{{ 72 = 72 }}}
OK