Question 1093907
Let {{{ a }}} = Aaron's age now
Let {{{ b }}} = Hunter's age now
Let {{{ c }}} = Kevin's age now
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(1) {{{ a = (1/2)*b + 4 }}}
(2) {{{ c = 4a - 31 }}}
(3) {{{ c + 5 = 3*( a + 5 ) - 25 }}}
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(1) {{{ 2a = b + 8 }}}
(1) {{{ 2a - b = 8 }}}
and
(3) {{{ c + 5 = 3a + 15 - 25 }}}
(3) {{{ c = 3a - 15 }}}
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Subtract (2) from (3)
(3) {{{ c = 3a - 15 }}}
(2) {{{ -c = - 4a + 31 }}}
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{{{ 0 = -a + 16 }}}
{{{ a = 16 }}}
and
(1) {{{ 2a - b = 8 }}}
(1) {{{ 2*16 - b = 8 }}}
(1) {{{ 32 - b = 8 }}}
(1) {{{ b = 24 }}}
and
(3) {{{ c = 3a - 15 }}}
(3) {{{ c = 3*16 - 15 }}}
(3) {{{ c = 48 - 15 }}}
(3) {{{ c = 33 }}}
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Kevin is 33 now
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check:
(1) {{{ a = (1/2)*b + 4 }}}
(1) {{{ 16 = (1/2)*24 + 4 }}}
(1) {{{ 16 = 12 + 4 }}}
(1) {{{ 16 = 16 }}}
OK
you can check (2) and (3)