Question 951004
Let {{{ f }}} = father's age now
Let {{{ s }}} = son's age now
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(1) {{{ f - 5 = 5*( s - 5 ) }}}
(2) {{{ f + 8 = 3*( s + 8 ) }}}
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(1) {{{ f - 5 = 5s - 25 }}}
(1) {{{ 5s - f = 20 }}}
and
(2) {{{ f + 8 = 3s + 24 }}}
(2) {{{ -3s + f = 16 }}}
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Add the equations
(1) {{{ 5s - f = 20 }}}
(2) {{{ -3s + f = 16 }}}
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{{{ 2s = 36 }}}
{{{ s = 18 }}}
and
(2) {{{ -3s + f = 16 }}}
(2) {{{ -3*18 + f = 16 }}}
(2) {{{ -54 + f = 16 }}}
(2) {{{ f = 70 }}}
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You are 70
Your son is 18
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check:
(1) {{{ f - 5 = 5*( s - 5 ) }}}
(1) {{{ 70 - 5 = 5*( 18 - 5 ) }}}
(1) {{{ 65 = 5*13 }}}
(1) {{{ 65 = 65 }}}
and
(2) {{{ f + 8 = 3*( s + 8 ) }}}
(2) {{{ 70 + 8 = 3*( 18 + 8 ) }}}
(2) {{{ 78 = 3*26 }}}
(2) {{{ 78 = 78 }}}
OK