First find the number of nougats by doubling the number of caramels: 3 caramels * 2 nougats/caramel = <<3*2=6>>6 nougats
Then find the number of truffles by adding 7 to the number of caramels: 3 caramels + 6 = <<3+6=9>>9 truffles
Then find the number of peanut clusters by subtracting the number of each other chocolate from the total number of chocolates: 50 chocolates - 3 caramels - 6 nougats - 9 truffles = <<50-3-6-9=32>>32 peanut clusters
Finally, divide the number of peanut clusters by the total number of chocolates and multiply by 100% to find the percentage chance he gets a peanut cluster: 32 peanut clusters / 50 chocolates *100% = 64%
#### 64