Scheme 1: The trader offers two successive discounts of 20% and 12.5% on the sale of each unit.
Scheme 2: The trader offers the buyer an option to 'pay for y units, get z units free'. The buyer realizes that if he needs to buy (y + z) units, it does not matter to him which of the two schemes he opts for.
Which of the following options gives a correct ordered pair of (y, z)?