Question
A contract on constrution job specifies a penalty for delay of completion beyond a certain date as follows: $₹ 200$ for the first day, $₹ 250$ for the second day, $₹ 300$ for the third day, etc, the penalty for each succeeding day being $₹ 50$ more than for the preceding day. How much money the contractor has to pay as penalty, if he has delayed the work by $30$ days?

