The numbers 1 to 7 are written on 7 pieces of paper and dropped into a box. Three of them are drawn at random. What is the probability that the three pieces of paper picked have numbers that are in arithmetic progression?
The price of diamond varies directly as square of its weight. The price of a 15 decigrams diamond is Rp33750. If diamond breaks into two pieces whose weights are in the ratio 2:3, find the loss incurred.