How do I figure out the genotype and how to draw the Punnett square for this question?

[Margaret!!!]

A male black gerbil was crossed with a tan female. The litter consisted of four black and five tan pups. One of the black females was back-crossed to her father (black), and their litter had sex black and two tan. One of the tan males was back-crossed to her mother (tan) and all their litter was tan.

What are the genotypes to the original black make and tan female?
How would I draw the punnett square?