To determine the cost to boil a full kettle of water, we can use the provided information step by step:
1. Identify the electricity consumption per kettle:
- A kettle uses [tex]\(0.2\)[/tex] units of electricity.
2. Determine the cost per unit of electricity:
- The cost of electricity is [tex]\(42\)[/tex] cents per unit.
3. Calculate the total cost to boil one kettle:
- First, multiply the total units of electricity used by the cost per unit:
[tex]\[
\text{Total cost} = \text{Electricity per kettle} \times \text{Cost per unit}
\][/tex]
[tex]\[
\text{Total cost} = 0.2 \times 42
\][/tex]
4. Perform the multiplication:
- [tex]\(0.2 \times 42 = 8.4\)[/tex] cents.
5. Round the result to the nearest cent:
- The result [tex]\(8.4\)[/tex] cents rounds to [tex]\(8\)[/tex] cents (to the nearest whole number).
So, the cost to boil a full kettle of water, rounded to the nearest cent, is [tex]\(8\)[/tex] cents.