Lay a 47-meter-long drainage pipe with two specifications of 5 meters and 2 meters. How many different laying methods are there for two different sizes of drainpipes? (no waste)
用5米和2米两种规格的排水管，铺设一段47米长的排水管道．两种不同规格的排水管有多少种不同的铺法？(不能有废料)
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