Final answer:
The standard form of the given expression is calculated by multiplying and adding the respective terms to get 0.351, corresponding to option D.
Step-by-step explanation:
The standard form of the expression 3x0.1 + 5x0.01 + 1x0.001 can be found by performing the multiplication and addition as follows:
- 3x0.1 = 0.3
- 5x0.01 = 0.05
- 1x0.001 = 0.001
- Adding these together: 0.3 + 0.05 + 0.001 = 0.351
Thus, the correct answer is 0.351, which matches with option D.