What is the expected genotype from this pairing?

In cats, black fur B is completely dominant to brown fur b. You have a brown fur, Manx cat that has mated with the neighbor cat (black fur, Manx tail). The neighbor cat had a brown fur- parent. There are 60 kittens born. Enter the number of kittens you d expect for each genotype: MMBB 0 MMBb 7.5 MMbb 7.5 MmBB 0 MmBb 15 Mmbb 15 mmBB 0 mmBb 7.5 mmbb 7.5 I got this, but it seems weird because why would they choose a number that leads to 7 cats, and a half? What I got wasn't the answer, so I'm just not clear on what the genotype is. The only thing I can think of is MM, but that means the neighbor cat is mating with a dead cat...