Answer this question on cash and profit?

A newspaper vendor sells the local evening paper for £1 a copy. The paper costs 80p a copy from the publisher. The vendor starts the day with 200 newspapers and £50 cash. By the end of the day he had sold 170 newspapers, and purchased for cash a further 150 newspapers for the following day. What is the difference (in £'S) between the profit for the day and the cash held at the end of the day? I've worked out the cash at £84, but i can't work out the profit. I've looked up the answer, and the difference between cash and profit is £66, but i cant work out how to get this.