Color blindness is a X-linked recessive trait. A couple want to predict whether it would be possible for their child to be color blind. The female is an unaffected carrier and the male is red/green color blind. What percentage of offspring would be color blind? 

There is a probability (n.b. NOT certainty) that half of all offspring will be colour blind.

Explanation: The female is XX and as an unaffected carrier we can assign genotype Cc where c is the recessive allele.

The male is XY and colour blind, so genotype cY

Male offspring can be cY or CY so p|colourblind = 50%

Female offspring can be Cc or cc so, again p= 50%

If there is also equal probability of sex of the offspring, there is an overall probability that half the offspring will be colour blind

the wires in the toaster turning red and the toast crisping and turning brown