and B each do a job. If it is all sunny, A needs 12 days and B needs 15 days to complete. On a rainy day, A’s work efficiency is 40% lower than that of a sunny day, and B’s is 10% lower. The two start work at the same time and finish at the same time. How many rainy days are there in the work?
甲乙两人各做一件工作．如果全是晴天，甲需12天，乙需15天可以完成．雨天甲的工作效率比晴天减少40%，乙减少10%，两人同时开工，恰好同时完成，问工作中有多少个雨天？
<result>10</result>