Question 698560
Let {{{ k }}} = Katies's age now
Let {{{ s }}} = Son's age now
{{{ k + 15 }}} = Katie's age in 15 yrs
{{{ s + 15 }}} = Son's age in 15 yrs
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given:
(1) {{{ k = 3s }}}
(2) {{{ k + 15 = 2*( s + 15 ) }}}
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Substitute (1) into (2)
(2) {{{ 3s + 15 = 2*( s + 15 ) }}}
(2) {{{ 3s + 15 = 2s + 30 }}}
(2) {{{ s = 30 - 15 }}}
(2) {{{ s = 15 }}}
and
(1) {{{ k = 3s }}}
(1) {{{ k = 3*15 }}}
(1) {{{ k = 45 }}}
Katie is 45, and in 15 yrs, she will be 60
check:
(2) {{{ k + 15 = 2*( s + 15 ) }}}
(2) {{{ 45 + 15 = 2*( 15 + 15 ) }}}
(2) {{{ 60 = 2*30 }}}
(2) {{{ 60 = 60 }}}
OK