Answer  50 cubic feet = 5.555 cubic yards

You can only convert cubic inches and cubic feet into cubic yards.. A cubic inch is 1 inch high by 1 inch long by 1inch deep. A cubic foot is 1 foot high by 1 foot long by 1 foot deep.  36 x 36 x36 inches is 1 cubic yard. 3 x 3 x 3 feet is one cubic yard. For instance, if you are buying redimix for a patio that is 10 ft x 10 feet x 4 inches deep you would need:

10 feet = 10 devided by 3 = 3.333 yards         4 inches = 4 devided by 36 or  0.1111 yards

3.33 x 3.33 x 0.1111 = 1.23 cubic yards