بسم الله الرحمن الرحيم
(1) Last year you paid 2.5 gram gold as zakah out of 100 gram gold, in this case now you have 97.5 gram gold. If it is so then this year you should pay fortieth part of the remaining gold as zakah. And if last year you paid the zakah of 100 gram gold by separate amount and this year that gold is in your possession as same then in such case you will have to pay the zakah of total 100 gram gold.
(2) In this case you will have to pay the zakah of cash amount and the gold.
Allah knows Best!
Darul Uloom Deoband