Mrs. Brown, Mrs. White, and Mrs. Gray are a teacher, a doctor, and a lawyer, not necessarily in that order. Each has a horse. One horse is white, one is brown, and one is gray. From the following clues, determine the occupation of each woman and the color of her horse. No one’s name is the same as the color of her horse. The teacher owns a brown horse. Mrs. Gray is a doctor.

Clue 3 is what we'll start with. Since Mrs. Gray is a doctor, this means that the doctor owns either a white horse or a brown horse. The doctor can't own a gray horse because the names can't match up (eg: the last name Gray with gray horse), due to clue 1.

If Mrs. Gray owned a brown horse, then she'd be a teacher (clue 2). But clue 3 says she's a doctor. We have a contradiction if Mrs. Gray owns the brown horse. Therefore, Mrs. Gray owns the white horse.

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After we concluded the last section, we now know the following:

The horses that are left are the brown and gray horse.
The professions left are the teacher and lawyer.
The people left are Mrs. Brown and Mrs. White.

In short, we've just crossed "Mrs. Gray", "doctor", and "white horse" from the list.

Based on clue 1, we know that Mrs. Brown cannot possibly own the brown horse. Therefore, she must own the gray horse. So Mrs. White must own the brown horse.

Since Mrs. White owns the brown horse, she must be the teacher (clue 2). That leaves "lawyer" as the last profession, and that's assigned to Mrs. Brown.

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Side note: I apologize for being a bit wordy, but I wanted to be very careful in the logical sense as to approach this problem. There's probably a much quicker efficient way to do this.