Question 800759
Let {{{ j }}} = Jack's age
Let {{{ p }}} = Priscilla's age
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(1) {{{ j = p + 11 }}}
(2) {{{ j + p = 153 }}}
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Subtract {{{ p }}} from both sides of (1)
(1) {{{ j - p = 11 }}}
Now add the equations
(1) {{{ j - p = 11 }}}
(2) {{{ j + p = 153 }}}
{{{ 2j = 164 }}}
{{{ j = 82 }}}
and, since
(1) {{{ j = p + 11 }}}
(1) {{{ 82 = p + 11 }}}
Subtract {{{ 11 }}} from both sides
(1) {{{ p = 71 }}}
Jack is 82 and Priscilla is 71