Question 1116219
Let {{{ a }}} = William's age now
Let {{{ b }}] = Daniel's age now
Let {{{ c }}} = William's mother's age now
Let {{{ d }}} = Daniel's sister's age now
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(1) {{{ a = b + 2 }}}
(2) {{{ c = 2a }}}
(3) {{{ b = 2d }}}
(4) {{{ c = d + 34 }}}
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From (2) and (4)
{{{ 2a = d + 34 }}}
From (3)
{{{ d = b/2 }}}
and
{{{ 2a = b/2 + 34 }}}
{{{ 4a = b + 68 }}}
From (1)
(1) {{{ b = a - 2 }}}
and
{{{ 4a = a - 2 + 68 }}}
{{{ 3a = 66 }}}
{{{ a = 22 }}}
and
(1) {{{ b = a - 2 }}}
(1) {{{ b = 22 - 2 }}}
(1) {{{ b = 20 }}}
and
(2) {{{ c = 2a }}}
(2) {{{ c = 2*22 }}}
(2) {{{ c = 44 }}}
and
(3) {{{ d = b/2 }}}
(3) {{{ d = 20/2 }}}
(3) {{{ d = 10 }}}
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William is 22
Daniel is 20 
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check:
(4) {{{ c = d + 34 }}}
(4) {{{ 44 = 10 + 34 }}}
(4) {{{ 44 = 44 }}}
OK
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