Sonia buys two off-cuts of ribbon in a sale. One is 153 cm long. The other is 204 cm long. She cuts them so that she ends up with a number of pieces all the same length. What is the greatest length each piece can be ?
A worker is paid R rupees per hours for the first 8 hours daily. For every hour after the first 8 hours, she is paid S rupees per hour. If she works 12 hours in one day, what is her average hourly for the day ?