__Ask a Question__

### Question Asked by a Student from EXXAMM.com Team

** Q 2938467302. ** A person is to count 4500 currency notes. Let ` a _{ n }` denote the number of notes he counts in the `n ^{ t h}` minute. lf `a _{1}= a _{2}=\ldots\ldots= a _{10}=150` and `a _{10}, a_{11}, ldots\ldots` are in A.P. with common difference(-2), then the time taken by him to count all notes is