The tripodasaurus has three legs. In a flock of tripodasauruses, there is a total of 20 heads and legs. How many tripodasauruses are in the flock?
Each animal has 1+3=<T>add(1, 3)=4 total heads and legs.
Then there are 20/4=<T>divide(20, 4)=5.0 in the flock.
