1. **Rounding 50 to three decimal places** The problem asks to round the number 50 to three decimal places. 2. **Understanding decimal places** Rounding to three decimal places means keeping three digits after the decimal point. 3. **Express 50 with three decimal places** Since 50 is a whole number, it can be written as 50.000 to three decimal places. 4. **Compare with the options** The correct rounded value is 50.000, which corresponds to option d. 5. **Solving the equation 100 - 5x = -100** We need to find the value of $x$ that satisfies the equation. 6. **Isolate the term with $x$** Subtract 100 from both sides: $$100 - 5x - 100 = -100 - 100$$ which simplifies to $$-5x = -200$$ 7. **Solve for $x$** Divide both sides by -5: $$x = \frac{-200}{-5} = 40$$ 8. **Check the options** The solution is $x = 40$, which corresponds to option b. **Final answers:** - Question 47: d. 50.000 - Question 48: b. x = 40