Please help , python tuple question

Please, help me
To solve this question using tuple in python.

Que. Pure Gems Store sells different varieties of gems to its customers.
Emerald, Ivory, Jasper, Ruby, Garnet and their prices are 1760, 2119, 1599, 3920, 3999
Write a Python program to calculate the bill amount to be paid by a customer based on the list
of gems and quantity purchased. Any purchase with a total bill amount above Rs.30000 is
entitled for 5% discount. If any gem required by the customer is not available in the store,
then consider total bill amount to be -1.
Assume that quantity required by the customer for any gem will always be greater than 0.
Perform case-sensitive comparison wherever applicable.