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This problem trains for: SAT-I, GMAT, AMC-8, Math Kangaroo 5-6.

2 years ago little Heidi was 5n/2 years old. 6 years from now, Heidi will be 9n/2 years old. How old is she now?

(character from Johanna Spyri's "Heidi")

In a span of 8 years, Heidi has aged 8 years:

equation

Solve for n:

equation

equation

equation

We add 2 to Heidi's age from 2 years ago to find her current age:

equation

Heidi is now 12 years old.