The ratio of the present age of Sandy to that of Molly is 7:2. Twelve years from now, the ratio of the ages of Sandy to Molly will be 5:2. What was Sandy's age 6 years ago? Choose the most appropriate option.
A) 39 B) 45 C) 51 D) 57 E) 63
Let the present age of Sandy be 7x years and that of Molly be 2x years.   (7x + 12) / (2x + 12) = 5 / 2   4x = 36   x = 9   Six years ago, Sandy's age was 7(9) - 6 = 57   The answer is 57.
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The ratio of the present age of Sandy to that of Molly is 7:2. Twelve years from now, the ratio of the ages of Sandy to Molly will be 5:2. What was Sandy's age 6 years ago?