SOLUTION:

Let,
x = cat
y = rabbit
z = dog

x + y = 10
z + y = 20
z + x= 24
z + x+ y = ?

x = 10- y
z = 20-y ...... (1)
z = 24-x ......(2)
z = 24-(10-y) ....(3)
z = 24-(10-{-z+20})
z = 24-(10 + z - 20)
z = 24 - 10 - z + 20
2z = 24-10+20
2z = 34
z = 17

z + y = 20
y = 20-z
y = 20-17= 3

z + x = 24
x = 24-z
x = 24-17
x = 7

z + x + y = 17+7+3= 27

Cat= 7kg.
Rabbit= 3kg
Dog= 17kg.

Q.E.D.

'kovich

SOME MATH FOR THE SOUL | madukovich's cogitations https://madukovich./2015/03/26/some-math-for-the-soul/