Treasure Chest Opened After Watching Ad

I watched an ad to open it. It was an old treasure chest from the Elf Forest, and I got a 500 gem package. That's a 5% chance. Old Treasure Chest from the Elf Forest Item Chance 500 Coins 0.1% 3,000 Gems 1.5% 5 Gem Booster: 1 Hour 1.6% 5 Gem Booster: 30 Mins 2.5% 1,000 Gems 3% 500 Gems 5% 10,000 EXP Up 18% 5,000 EXP Up 28% 3,000 EXP Up 40.3%