Question 808149
Let {{{ j }}} = Jack's age now
Let {{{ s }}} = Susan's age now
{{{ j + 5 }}} = Jack's age 5 yrs from now
{{{ s + 5 }}} = Susan's age 5 yrs from now
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(1) {{{ j = s + 27 }}}
(2) {{{ j + 5 = 4*( s + 5 ) }}}
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(2) {{{ j + 5 = 4s + 20 }}}
(2) {{{ j - 4s = 15 }}}
and
(1) {{{ j - s = 27 }}}
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Subtract (2) from (1)
(1) {{{ j - s = 27 }}}
(2) {{{ -j + 4s = -15 }}}
{{{ 3s = 12 }}}
{{{ s = 4 }}}
and
(1) {{{ j = s + 27 }}}
(1) {{{ j = 4 + 27 }}}
(1) {{{ j = 31 }}}
Jack is 31 and Susan is 4
check:
(2) {{{ j + 5 = 4*( s + 5 ) }}}
(2) {{{ 31 + 5 = 4*( 4 + 5 ) }}}
(2) {{{ 36 = 4*9 }}}
(2) {{{ 36 = 36 }}}
OK