Question 807886
Let {{{ m }}} = my age now
Let {{{ b }}} = my brother's age now
{{{ m + 2 }}} = my age in 2 years
{{{ b + 2 }}} = my brother's age in 2 years
Let {{{ n }}} = the number of years from now
when my brother will be 1/2 my age
{{{ b + n }}} = my age in {{{ n }}} years
{{{ m + n }}} = my brother's age in {{{ n }}} years
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(1) {{{ m = 4b }}}
(2) {{{ m + 2 = 3*( b + 2 ) }}}
(3) {{{ b + n = (1/2)*( m + n ) }}}
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This is 3 equations and 3 unknowns, so it's solvable
Substitute (1) into (2)
(2) {{{ 4b + 2 = 3b + 6 }}}
(2) {{{ b = 4 }}}
and, since
(1) {{{ m = 4b }}}
(1) {{{ m = 16 }}}
and
(3) {{{ b + n = (1/2)*( m + n ) }}}
(3) {{{ 4 + n = (1/2)*( 16 + n ) }}}
(3) {{{ 8 + 2n = 16 + n }}}
(3) {{{ n = 8 }}}
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In 8 years will my brother be 1/2 my age
check:
In 8 yrs I will be {{{ 16 + 8 = 24 }}}
In 8 yrs my brother will be {{{ 4 + 8 = 12 }}}
He is half my age
OK