Question 514361
Let {{{k}}} = Kevin's age now
Let {{{e}}} = Ed's age now
Let {{{b}}} = Bob's age now
given:
(1) {{{ k = e - 2 }}}
(2) {{{ e = (2/3)*b + 6 }}}
(3) {{{ b = 5*(1/4)*k }}}
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This is 3 equations and 3 unknowns, so it
should be solvable
(1) {{{ e = k + 2 }}}
By substitution:
(2) {{{ k + 2 = (2/3)*b + 6 }}}
(2) {{{ 3k + 6 = 2b + 18 }}} 
(2) {{{ 2b = 3k - 12 }}}
(2) {{{ b = (3/2)*k - 6 }}}
By substitution:
(3) {{{ (3/2)*k - 6 = (5/4)*k }}}
Multiply both sides by {{{4}}}
(3) {{{ 6k - 24 = 5k }}}
(3) {{{ k = 24 }}}
and
(1) {{{ e = k + 2 }}}
(1) {{{ e = 24 + 2 }}}
(1) {{{ e = 26 }}}
and
(2) {{{ b = (3/2)*k - 6 }}}
(2) {{{ b = (3/2)*24 - 6 }}} 
(2) {{{ b = 30 }}}
Kevin is 24
Ed is 26 
Bob is 30