Final answer:
Mrs. Reyes sells 2/3 of her 15 Ukay dresses, which is 10 dresses. Subtracting these from the original 15 dresses, she has 5 dresses left. The answer is option (b) 5.
Step-by-step explanation:
The question requires understanding of basic fractions and arithmetic operations. Mrs. Reyes had 15 Ukay dresses. If she sells 2/3 of them, this means she sells 2/3 * 15 = 10 dresses. To find out how many dresses are left, subtract the number of dresses sold from the total number of dresses she had initially: 15 - 10 = 5 dresses left.
So, the answer to the question is (b) 5.