有8个谜语让60个人猜，猜对共338人次。每人至少猜对3个，猜对3个的有6人，猜对4个的有10人，猜对5和7个的人数同样多。8个谜语全猜对的有多少人？（用算术解法或方程解法）

数学题解答：有2种算法，先看算术方法：

未猜对次数：60×8-338=142(人)
猜对5个，6个，7个的人数是：
[142-(8-3)×6-(8-4)×10]÷(8×3-5-6-7)=12(人)
8个全猜对的有：
60-6-10-3×12=8(人)
答：8个全猜对的有8人。

再看方程解法：

解：设猜对8个有X人。
8X+3×6+4×10+（60-X-6-10）÷3×（5+6+7）=338
8X+18+40+（44-X）×6=338
8X+18+40+264-6X=338
2X=16
X=8

答：8个全猜对的有8人。

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