Question 433478
Let {{{a}}} = Jane's age now
Let {{{b}}} = Jame's age now
given:
(1) {{{ a - 4 = 2*(b - 4) }}}
(2) {{{ b + 4 = (3/4)*(a + 4) }}}
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(1) {{{ a - 4 = 2b - 8 }}}
(1) {{{ a - 2b = -4 }}}
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(2) {{{ b + 4 = (3/4)*a + 3 }}}
(2) {{{ 4b + 16 = 3a + 12 }}}
(2) {{{ 3a - 4b = 4 }}}
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Multiply both sides of (1) by {{{2}}}
and subtract (1) from (2)
(2) {{{ 3a - 4b = 4 }}}
(1) {{{ -2a + 4b = 8 }}}
{{{ a = 12 }}}
and
(1) {{{ 12 - 2b = -4 }}}
(1) {{{ 2b = 12 + 4 }}}
(1) {{{ 2b = 16 }}}
{{{ b = 8 }}}
12 is Jane's age now
8 is Jame's age now
check answer
(1) {{{ a - 4 = 2*(b - 4) }}}
(1) {{{ 12 - 4 = 2*(8 - 4) }}}
(1) {{{ 8 = 2*4 }}}
{{{ 8 = 8 }}}
OK
(2) {{{ b + 4 = (3/4)*(a + 4) }}}
(2) {{{ 8 + 4 = (3/4)*(12 + 4) }}}
(2) {{{ 12 = (3/4)*16 }}}
(2) {{{ 48 = 48 }}}
OK