[leopud]

C + R = 10
d + R = 20
d + c = 24
C+d+R=x
10 – c = 20 – d
d – c = 10
d+c=24
d = 10 + c
d = 24 – c
10+c = 24-c
2c=14
c=7
d=17
R=3
C+d+R=27

[4Liberty]

10 + 20 = 24 - 2X

30 - 24 = -2X

-6 = -2X

3 = rabbit

3 + 24 = all three