Question 512420
Call the ones digit {{{c}}}
Call the tens digit {{{b}}}
Call the hundreds digit {{{a}}}
given:
(1) {{{ b = 2a }}}
(2) {{{ c = b + 3 }}}
(3) {{{ c = b + a }}}
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Substitute (2) into (3)
(3) {{{ b + 3 = b + a }}}
Subtract {{{b}}} from both sides
(3) {{{ a = 3 }}}
and
(1) {{{ b = 2a }}}
(1) {{{ b = 6 }}}
and
(3) {{{ c = b + a }}}
(3) {{{ c = 6 + 3 }}}
(3) {{{ c = 9 }}}
The number is 369