Final answer:
The number of blue sweets is determined by dividing the total number of sweets by the sum of the parts in the ratio and then multiplying by the number of parts for blue sweets, which results in 10 blue sweets.
Step-by-step explanation:
To determine the number of blue sweets when the sweets are divided in the ratio 3:5:2, you first need to understand that the sum of the parts of the ratio represents the total number of parts. In this case, 3 (red) + 5 (green) + 2 (blue) equals 10 parts. Since we know there are a total of 50 sweets, each part represents 50 sweets divided by 10 parts, which is 5 sweets per part. Therefore, to find the number of blue sweets which is 2 parts, you multiply the number of sweets per part by 2. This calculation gives you 5 sweets per part times 2 parts which equals 10 blue sweets.