2. Four people, A, B, C, and D, planted a total of 60 trees. It is known that, the number of trees planted by A is half of the rest three, the number of trees planted by B is one-third of the rest three, and the number of trees planted by C is one-fourth of the rest three. How many trees did D plant $\qquad$?
【Answer】 13
【Analysis】
A $=$ one third of the total $=20$, B $=$ one quarter of the total $=15$, C $=$ one fifth of the total $=12$, so D $=60-20-15-12=13$ (trees)