Chickens have 2 legs and sheep have 4 legs. If x is the number of chickens and y is the number of sheep, then we have the system of equations: x + y = 48, 2 x + 4 y = 134. We can solve this system : x = 48 - y, then we will put it into the 2nd equation: 2 * ( 48 - y ) + 4 y = 134, 96 - 2 y + 4 y = 134, 2 y = 134 - 96, 2 y = 38, y = 38 : 2, y = 19. Answer: Farmer Tom has 19 sheep.