The mode is 33 because it is listed 3x's.
So 16 = 3.6, 10 = 2.3 so 20 = 4.6 then add 16 + 20 to get 36 so 3.6 + 4.6 = 8.2
36 ounces = 8.2 cups
36 = 8.2, 8 = 1.8, 20 = 4.6, 36 + 8 + 20 = 64 ounces so 8.2 + 1.8 + 4.6 = 14.6 cups
64 ounces = 14.6 cups
Total cups = 8.2 + 14.6 = 22.8 cups
Silver = 10%
Gold = 90%
Amount of gold to be deducted
90/100 × 18 = 16.2 g
75/100 × 18 = 13.5
16.2 - 13.5 = 2.7
Amount o silver to added.
2.7 × 5 = 13.5
Answer = 13.5 g