Question 1140064

Amy is one third the age of her mother.

 In 12 years time, Amy will be half the age of her mother.

How old is Amy’s mother?
<pre>Let Amy's mother's age be M
Then Amy's = {{{matrix(1,3, (1/3)M, or, M/3)}}}
We then get: {{{matrix(1,7, M/3 + 12, "=", (1/2)(M + 12), "======>", M/3 + 12, "=", (M + 12)/2)}}}
2M + 72 = 3(M + 12) -------- Multiplying by LCD, 6
2M + 72 = 3M + 36
2M - 3M = 36 - 72
- M = - 36
Amy's mother, or: {{{highlight_green(matrix(1,6, M, "=", (- 36)/(- 1), "=", 36, years-old))}}}