Answer:
The answer should be 3cm
Explanation:
The way you worded it was kind of confusing so pardon me if the answer isnt the correct answer you were looking for. But I suppose that if 1 cm is 50 in. than 150 in. would be 3 cm. Because 50 + 50 + 50 = 150. And if it is 1 cm. per 50 in. than that would be 3 cm. I hope this answered your question! And if not.. again, im sorry.