191. What is the 5-digit number (including zero) in which the last digit is twice the first, the second digit is the difference between the third and the first, and the fourth digit is the sum of the first and third added and then subtracted from the fifth.
194. There are 10 baskets. Each of the 9 baskets have 10 balls weighing 10 kg each, except for one basket which has 10 balls weighing only 9 kg each. All the balls and baskets are identical in appearance. You are asked to determine which basket contains the 9 kg balls. You can only take a single measurement using a weighing machine (the balls can be taken out from the baskets but still you can only take one measurement). How would you do it?
198. Somehow or other I got talked into buying something on the installment plan. I'm not sure I got a good deal. The payments to date, according to my checkbook, have reached $96. The second year cost $2.00 more than the first year; the third year cost $3.00 more than the second; and the fourth year cost me $4.00 more than the third. What were my payments the first year?
199. Matt gave John as many dollars as John started out with. John then gave Matt back as much as Matt had left. Matt then gave John back as many dollars as John had left, which left Matt broke and gave John a total of $80.00. How much did Matt and John have at the beginning of their exchange?