Let the dominant long fur be represented by L and the recessive short fur be l. The parents are therefore:
Ll x Ll
This cross produces the following offspring:
LL, Ll, Ll and ll
From the above cross, we can see that there is a 3/4 chance of an offspring with long fur and a 1/4 chance of an offspring with short fur. Now, calculating:
a) Three short fur babies means the event has to happen in successions thrice, which implies multiplication in probability. This is:
P(3 short fur) = 1/4 * 1/4 * 1/4
P(3 short fur) = 1/64
b) the same method is used for babies with long fur:
P(3 long fur) = 3/4 * 3/4 * 3/4
P(3 long fur) = 27/64