For this question you have to start by knowing three things:
1) Colorblindness is a sex linked trait
2)It is also recessive
3) Carrier means heterozygous
If you are able to, draw out a Punnett square depicting the offspring ratios. You should get a 2 girls 2 boy in a 4-squared Punnett square. A female will always get one X from their mother and one X from their father. If the trait is recessive, having only one affected X (out of two X's, for the female) will not cause colorblindness. For a male, however, he will get one X from the mother and one Y from the father. This means that if the son happens to get the affect X from mom then he will be color blind because the Y does not counteract the X, like how it works for females.
If this is the case, having a male child would require a 1/2 chance. Being colorblind in this scenario is a 1/4 chance.
To find the possibility of having a child that is both male and colorblind, multiply 1/4 by 1/2
