Question 1130667
Let {{{ a }}} = man's age now
Let {{{ b }}} = son's age now
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(1) {{{ a - 6 = 4*( b - 6 ) }}}
(2) {{{ a + 12 = 2*( b + 12 ) }}}
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(1) {{{ a - 6 = 4b - 24 }}}
(1) {{{ -a + 4b = 18 }}}
and
(2) {{{ a + 12 = 2b + 24 }}}
(2) {{{ a - 2b = 12 }}}
Add the equations
{{{ 2b = 30 }}}
{{{ b = 15 }}}
and
(1) {{{ a - 6 = 4*( 15 - 6 ) }}}
(1) {{{ a - 6 = 36 }}}
(1) {{{ a = 42 }}}
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The man is 42
His son is 15
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check:
(1) {{{ a - 6 = 4*( b - 6 ) }}}
(1) {{{ 42 - 6 = 4*( 15 - 6 ) }}}
(1) {{{ 36 = 4*9 }}}
(1) {{{ 36 = 36 }}}
OK
Check other equation