Question 1145067
Let {{{ a }}} = Clarence's age now
Let {{{ b }}} = his father's age now
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(1) {{{ a + b = 39 }}}
(2) {{{ b + 4 = 5*( a + 4 ) - 1 }}}
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(2) {{{ b + 4 = 5a + 20 - 1 }}}
(2) {{{ 5a - b = -19 + 4 }}}
(2) {{{ 5a - b = -15 }}}
Add (1) and (2)
{{{ 6a = 24 }}}
{{{ a = 4 }}}
and
(1) {{{ 4 + b = 39 }}}
(1) {{{ b = 35 }}}
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Clarence is 4
His father is 35
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check:
(2) {{{ b + 4 = 5*( a + 4 ) - 1 }}}
(2) {{{ 35 + 4 = 5*( 4 + 4 ) - 1 }}}
(2) {{{ 39 = 5*8 - 1 }}}
(2) {{{ 39 = 39 }}}
OK