A cuboid of 1000gms has 20% of pure gold. How much more gold need to be added to get the percentage level to 50%

Question

A cuboid of 1000gms has 20% of pure gold (we have 200gms of gold). How much more gold need to be added to get the percentage level to 50%

Answer 1

1000(.20) + x = (1000+x).50 = 500 +.5x

200 +x = 500 +.5x

.5x = 300

x = 600 grams of pure gold need to be added to get 50%