Question 1156131
Let {{{ a }}} = Mr. K's age now
Let {{{ b }}} = Eric's age now
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(1) {{{ a = 5b }}}
(2) {{{ a + 10 = 3*( b + 10 ) }}}
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(2) {{{ a + 10 = 3b + 30 }}}
(2) {{{ a = 3b + 20 }}}
Plug (1) into (2)
(2) {{{ 5b = 3b + 20 }}}
(2) {{{ 2b = 20 }}}
(2) {{{ b = 10 }}}
and
(1) {{{ a = 5b }}}
(1) {{{ a = 5*10 }}}
(1) {{{ a = 50 }}}
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Mr. K is 50
Eric is 10 
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check:
In 10 yrs Mr. K is 60
In 10 yrs Eric is 20
60 is 3 times 20
OK