Question 716050
(1) {{{ a + b + c = 59 }}}
(2) {{{ a = c + 1 }}}
(3) {{{ c = b - 1 }}}
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(3) {{{ b = c + 1 }}}
Substitute (2) and (3) into (1)
(1) {{{ c + 1 + c + 1 + c = 59 }}}
(1) {{{ 3c + 2 = 59 }}}
(1) {{{ 3c = 57 }}}
(1) {{{ c = 19 }}}
and
(2) {{{ a = c + 1 }}}
(2) {{{ a = 19 + 1 }}}
(2) {{{ a = 20 }}}
and
(3) {{{ b = c + 1 }}}
(3) {{{ b = 19 + 1 }}}
(3) {{{ b = 20 }}}
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check:
(1) {{{ 20 + 20 + 19 = 59 }}}
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{{{ a - 7 = 20 - 7 }}}
{{{ a - 7 = 13 }}}
and
{{{ b - 7 = 13 }}}
and
{{{ c - 7 = 19 - 7 }}}
{{{ c = 12 }}}
7 yrs ago, Art and Ben were teenagers