Question 445517
Let {{{s}}} = Steve's age now
Let {{{t}}} = Tin's age now
given:
(1) {{{ s + t = 72 }}}
(2) {{{ s + 12 = 6*( t - 21) }}}
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(1) {{{ s = 72 - t }}} )
By substitution:
(2) {{{ 72 - t + 12 = 6*( t - 21) }}}
(2) {{{ 72 - t + 12 = 6t - 126 }}}
(2) {{{ 7t = 72 + 12 + 126 }}}
(2) {{{ 7t = 210 }}}
{{{ t = 30 }}}
and, since,
(1) {{{ s + t = 72 }}}
(1) {{{ s + 30 = 72 }}}
(1) {{{ s = 42 }}}
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(1.1) Steve is 42 and Tim is 30
(1.2) The difference in their ages never changes,
so, it was 12 years difference