Question 1087040
Let {{{ u }}} = the units digit
Let {{{ t }}} = the tens digit
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(1) {{{ 10t + u = 3*( t + u ) - 2 }}}
(2) {{{ 10t + u + 54 = 10u + t }}}
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(1) {{{ 10t + u = 3t + 3u - 2 }}}
(1) {{{ 7t - 2u = -2 }}}
and
(2) {{{ 9t - 9u = -54 }}}
(2) {{{ t - u = -6 }}}
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Multiply both sides of (2) by {{{ 2 }}}
and subtract (2) from (1)
(1) {{{ 7t - 2u = -2 }}}
(2) {{{ -2t + 2u = 12 }}}
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{{{ 5t = 10 }}}
{{{ t = 2 }}}
and
(2) {{{ t - u = -6 }}}
(2) {{{ 2 - u = -6 }}}
(2) {{{ -u = -8 }}}
(2) {{{ u = 8 }}}
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The number is 28 
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check:
3 times the sum of it's digits:
{{{ 3*( 2 + 8 ) = 30 }}}
{{{ 30 - 2 = 28 }}}
OK
Add 54 to the number:
{{{ 28 + 54 = 82 }}}
The number is reversed
OK