Question 657990
Let {{{ m }}} = Mother's age no
Let {{{ s }}} = Son's age now
given:
(1) {{{ m = 3s + 6 }}}
(2) {{{ m - 4 = 5*( s - 4 ) }}}
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Substitute (1) into (2)
(2) {{{ 3s + 6 - 4 = 5*( s - 4 ) }}}
(2) {{{ 3s + 2 = 5s - 20 }}}
(2) {{{ 2s = 20 + 2 }}}
(2) {{{ 2s = 22 }}}
(2) {{{ s = 11 }}}
Son is 11
check:
(1) {{{ m = 3*11 + 6 }}}
(1) {{{ m = 39 }}}
and
(2) {{{ 39 - 4 = 5*( s - 4 ) }}}
(2) {{{ 35 = 5s - 20 }}}
(2) {{{ 5s = 55 }}}
(2) {{{ s = 11 }}}
OK