Amogh buys three items at the store for exactly Rs 100. The second item costs half as much as the first item, and the third item is half as much as the second.
How much did each one cost?

There is a clothing store in Bartlesville.
The owner has devised his own method of pricing items.
A vest costs $20, socks cost $25, a tie costs $15 and a blouse costs $30.
Using the method, how much would a pair of underwear cost?