SOLUTION: sally is 12 years old and her uncle mike is 3 times as old. How many years must pass before her uncle mike is only twice as old as sally? how many years ago was uncle mike 7 times

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Question 498494: sally is 12 years old and her uncle mike is 3 times as old. How many years must pass before her uncle mike is only twice as old as sally? how many years ago was uncle mike 7 times as old.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+3%2A12+=+36+ is Mike's age now
Let x = number of years from now
when uncle is twice Sally's age
(a)
+2%2A%2812+%2B+x%29+=+36+%2B+x+
+24+%2B+2x+=+36+%2B+x+
+x+=+36+-24+
+x+=+12+
In 12 years Sally will be 24
In 12 years Uncle will be 48,
twice Sally's age
(b)
Let y = number of years ago when Uncle was
7 times as old as Sally
+7%2A%28+12+-+y+%29+=+36+-+y+
+84+-+7y+=+36+-+y+
+6y+=+84+-+36+
+6y+=+48+
+y+=+8+
8 years ago, Uncle was +36+-+8+=+28+
8 years ago, Sally was +12+-+8+=+4+
Uncle was 7 times her age