Question 1057696
Let {{{ p }}} = Peter's age now
Let {{{ j }}} = Juan's age now
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(1) {{{ p = j + 7 }}}
(2) {{{ p = 5j + 3 }}}
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(1) {{{ p - j = 7 }}}
(2) {{{ p - 5j = 3 }}}
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Subtract (2) from (1)
(1) {{{ p - j = 7 }}}
(2) {{{ -p + 5j = -3 }}}
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{{{ 4j = 4 }}}
{{{ j = 1 }}}
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Find {{{ j + 9 }}}
{{{ j + 9 = 1 + 9 }}}
{{{ j + 9 = 10 }}}
Juan will be 10 in 9 yrs
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check:
(1) {{{ p = j + 7 }}}
(1) {{{ p = 1 + 7 }}}
(1) {{{ p = 8 }}}
and
(2) {{{ p = 5j + 3 }}}
(2) {{{ p = 5*1 + 3 }}}
(2) {{{ p = 8 }}}
OK