Answer:
120
Step-by-step explanation:
n^2 has a factor of 18, so factors of 3^2·2. Since n^2 is a perfect square, we know n must have a factor of 3·2 = 6.
n^3 has a factor of 640, so factors of 2^7·5. Since n^3 is a perfect cube, we know n must have a factor of 2^3·5 = 40.
The least common multiple of 6 and 40 is 120.
The smallest positive integer n is 120.
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Check
120^2/18 = 800
120^3/640 = 2700
