SOLUTION: seven years ago, Mary was 6 times as old as Cora. in one year, she will be only twice as old as Cora. Find their present ages.

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Question 463455: seven years ago, Mary was 6 times as old as Cora. in one year, she will be only twice as old as Cora. Find their present ages.
Answer by amoresroy(361) About Me  (Show Source):
You can put this solution on YOUR website!
Let M = age of Mary
C = age of Cora
1st equation:
M-7 = 6(C-7)
M-7 = 6C-42
2nd equation:
M+1 = 2(C+1)
M+1 = 2C+2
Subtract the 1st equation by 2nd equation to eliminate M
-7-1 = 6C-42-2c-2
-8+44 = 4C
4C = 36
C = 9
Substitute C = 9 in 2nd equation to get
M+1 = 2*9 +2
M = 19
Mary is 19 years old.
Cora is 9 years old.