Question 941684
The language is a little tricky here
Hope I'm interpreting it right
Let {{{ m }}} = Mary's age now
Let {{{ s }}} = her son's age now
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(1) {{{ s -5 = (1/5)*( m - 5 ) }}}
(2) {{{ 3*( s + 5 ) = ( m + 5 ) + 8 }}}
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(1) {{{ 5*( s - 5 ) = m - 5 }}}
(1) {{{ 5s - 25 = m - 5 }}}
(1) {{{ 5s - m = 20 }}}
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(2) {{{ 3s + 15 = m + 13 }}}
(2) {{{ -3s + m = 2 }}}
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Add the equations
(1) {{{ 5s - m = 20 }}}
(2) {{{ -3s + m = 2 }}}
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{{{ 2s = 22 }}}
{{{ s = 11 }}}
plug this back into (1) or (2)
(2) {{{ -3s + m = 2 }}}
(2) {{{ -3*11 + m = 2 }}}
(2) {{{ -33 + m = 2 }}}
(2) {{{ m = 35 }}}
Mary's current age is 35
check:
(1) {{{ 5s - m = 20 }}}
(1) {{{ 5*11 - 35 = 20 }}}
(1) {{{ 55 - 35 = 20 }}}
(1) {{{ 20 = 20 }}}
OK