Question 824184
Let {{{ f }}} = father's age now
Let {{{ s }}} = son's age now
{{{ f - 3 }}} = father's age 3 yrs ago
{{{ s - 3 }}} = son's age 3 yrs ago
given:
(1) {{{ s + f = 46 }}}
(2) {{{ f - 3 = 4*( s - 3 ) }}}
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(2) {{{ f - 3 = 4s - 12 }}}
(2) {{{ 4s - f = 9 }}}
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Add (1) and (2)
(1) {{{ s + f = 46 }}}
(2) {{{ 4s - f = 9 }}}
{{{ 5s = 55 }}}
{{{ s = 11 }}}
and, since
(1) {{{ s + f = 46 }}}
(1) {{{ f = 46 - 11 }}}
(1) {{{ f = 35 }}}
The father is 35 and the son is 11
check:
(2) {{{ f - 3 = 4*( s - 3 ) }}}
(2) {{{ 35 - 3 = 4*( 11 - 3 ) }}}
(2) {{{ 32 = 4*8 }}}
(2) {{{ 32 = 32 }}}
OK