1. The problem asks to identify a factor of 10. 2. A factor of a number is an integer that divides the number exactly without leaving a remainder. 3. The factors of 10 are numbers that divide 10 evenly: 1, 2, 5, and 10. 4. From the given options: 30, 50, 3, 7, and 5, we check which divides 10 exactly. 5. 5 divides 10 exactly since $$10 \div 5 = 2$$ with no remainder. 6. The other numbers do not divide 10 evenly. 7. Therefore, the factor of 10 from the options is 5.