Question 837799
Let {{{ s }}} = Jose's sister's age now
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(1) {{{ 11 + 1 = 4*( s + 1 ) }}}
(1) {{{ 12 = 4s + 4 }}}
(1) {{{ 4s = 8 }}}
(1) {{{ s = 2 }}}
His sister is {{{ 2 }}} now
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Let {{{ n }}} = the number of years from now
when Jose will be twice his sister's age
(2) {{{ 11 + n = 2*( 2 + n ) }}}
( note that {{{ 11 }}} and {{{ 2 }}} are their present ages )
(2) {{{ 11 + n = 4 + 2n }}}
(2) {{{ 11 = 4 + n }}}
(2) {{{ n = 7 }}}
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In 7 years Jose will be twice his sister's age
check:
In 7 years, Jose will be {{{ 11 + 7 = 18 }}}
In 7 years, his sister will be {{{ 2 + 7 = 9 }}}
18 is twice 9
OK