SOLUTION: Jose is 11 years old. Next year he will be 4 times as old as his sister will be then. How many years from now will he be twice as old as his his sister will be them

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Question 837799: Jose is 11 years old. Next year he will be 4 times as old as his sister will be then. How many years from now will he be twice as old as his his sister will be them
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = Jose's sister's age now
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(1) +11+%2B+1+=+4%2A%28+s+%2B+1+%29+
(1) +12+=+4s+%2B+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+%2B+n+=+2%2A%28+2+%2B+n+%29+
( note that +11+ and +2+ are their present ages )
(2) +11+%2B+n+=+4+%2B+2n+
(2) +11+=+4+%2B+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+%2B+7+=+18+
In 7 years, his sister will be +2+%2B+7+=+9+
18 is twice 9
OK