Question 1100468
Let {{{ a }}} = Joe's age now
Let {{{ b }}} = George's age now
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(1) {{{ b - 5 = 3*( a - 5 ) }}}
(2) {{{ a + b = 42 }}}
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(1) {{{ b - 5 = 3a - 15 }}}
(1) {{{ 3a - b = 10 }}}
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Add (1) and (2)
(2) {{{ a + b = 42 }}}
(1) {{{ 3a - b = 10 }}}
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{{{ 4a = 52 }}}
{{{ a = 13 }}}
and
(2) {{{ 13 + b = 42 }}}
(2) {{{ b = 29 }}}
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Joe is 13 now
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check:
(1) {{{ b - 5 = 3*( a - 5 ) }}}
(1) {{{ 29 - 5 = 3*( 13 - 5 ) }}}
(1) {{{ 24 = 3*8 }}}
(1) {{{ 24 = 24 }}}
OK