21. You have 420 tons of below deck tonnage and 150 tons of above deck cargo on board. You must load 135 tons of liquid mud below deck. How much more deck cargo can you load

After loading 135 tons of liquid mud, the vessel has 555 tons below deck. The loading diagram limits deck cargo to 240 tons at this below deck tonnage, and with 150 tons already loaded, an additional 90 tons can be safely loaded.