Question 1020402
Let {{{ j }}} = Jay's age now
Let {{{ m }}} = Mary's age now
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(1) {{{ j - 5 = 7*( m - 5 ) }}}
(2) {{{ m + 5 = (1/2)*( j + 5 ) }}}
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(1) {{{ j - 5 = 7m - 35 }}}
(1) {{{ 7m - j = 30 }}}
and
(2) {{{ 2m + 10 = j + 5 }}}
(2) {{{ -2m + j = 5 }}}
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Add (1) and (2)
(1) {{{ 7m - j = 30 }}}
(2) {{{ -2m + j = 5 }}}
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{{{ 5m = 35 }}}
{{{ m = 7 }}}
and
(2) {{{ -2m + j = 5 }}}
(2) {{{ -2*7 + j = 5 }}}
(2) {{{ -14 + j = 5 }}}
{{{ j = 19 }}}
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Mary is 7
Jay is 19
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check:
(2) {{{ m + 5 = (1/2)*( j + 5 ) }}}
(2) {{{7 + 5 = (1/2)*(19 + 5 ) }}}
(2) {{{ 12 = (1/2)*24 }}}
(2) {{{ 12 = 12 }}}
OK
You can check (1)