how can 375 000 ?
15 000 * 25? no, you just need 15 000 tokens to buy premium pass. Then you will get premium rewards once you have enough coins every tier. But unfortunately, until today, no one reach Tier 25 by doing Quest.
You can buy premium pass later. if you buy premium pass when you Tier 25, You will get All rewards from Tier 1 - 25.