how to solve probability problems

- A house is infested with mice and to combat this, the householder acquired 4 cats, Albert, Belinda, Khalid and Poon. The householder observes that only half of the creatures caught are mice. A fifth are voles and the rest are birds. 20% of the catches are made by Albert, 45% by Belinda, 10% by Khalid and 25% by Poon.

a). The probability of a catch being a mouse, a bird or a vole is independent of whether it is made by Albert. What is the probability of a randomly selected catch

i) Being a mouse caught by Albert [2]

ii). Bird not caught by Albert [2]