Question 587649
Let {{{ a }}} = Mark's age now
Let {{{ b }}} = Matt's age now
{{{ a - 4 }}} = Mark's age 4 years ago
{{{ b - 2 }}} = Matt's age 2 years ago
given:
(1) {{{ 4a = 8*( b - 2 ) + 4 }}}
(2) {{{ 3b = a - 4 + 3 }}}
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(1) {{{ 4a = 8b - 16 + 4 }}}
(1) {{{ 4a - 8b = -12 }}}
and
(2) {{{ a - 3b = 4 - 3 }}}
(2) {{{ a - 3b = 1 }}}
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Multiply both sides of (2) by {{{4}}}
and subtract (1) from (2)
(2) {{{ 4a - 12b = 4 }}}
(1) {{{ -4a + 8b = 12 }}}
{{{ -4b = 16 }}}
{{{ b = -4 }}}
I get a negative number which means 4 years
before he was born. Can you find my mistake?
I don't see one.