Question 903242
Let {{{ r }}} = Ray's age now
Let {{{ b }}} = his brother's age now
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(1) {{{ r = 3b }}}
(2) {{{ r + 7 = 2*( b + 7 ) }}}
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(2) {{{ r + 7 = 2b + 14 }}}
(2) {{{ r = 2b + 7 }}}
Substitute (1) into (2)
(2) {{{ 3b = 2b + 7 }}}
(2) {{{ b = 7 }}}
and
(1) {{{ r = 3b }}}
(1) {{{ r = 3*7 }}}
(1) {{{ r = 21 }}}
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Ray is 21
His brother is 7
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check:
(2) {{{ r + 7 = 2b + 14 }}}
(2) {{{ 21 + 7 = 2*7 + 14 }}}
(2) {{{ 28 = 14 + 14 }}}
(2) {{{ 28 = 28 }}}
OK