Math game

[GrandizerII]

Here's a new one. Don't miss anything this time

F = Frog
S = Sheep
H = Horse

F+H=20 and S+H=24

S+H-F-H=24-20 => S-F=4 => the difference in kg between the sheep and the frog is 4

So F+S=10 => F + F+4 = 10 => 2F+4=10 => 2F=6 => F = 3

F = 3 => S = 7 => H = 17

Answer is 27 (you can also deduce this without ever knowing the horse's weight just by comparing the pictures).