1，有一个老人想以投资的方式来对他的退休做计划。他准备第一年一个月投资100元，第二年一个月投资200元，第三年一个月投300元，照这样的规律下去，他需要多少年能够总投资数额达66000元？
2，第二道不明白什么意思，翻译不来，高手求救：
Danielle's chemistry professor has a complicated grading system.Each lab counts once and each test counts as two labs.At the end of the semester there is a final lab that counts as three regular labs.Danielle received scores of 84,87.and 93 on her labs, and scores of 89 and 94 on her tests.What score must she get on the final lab to receive an A (an A is 90)?
谢了