The number of seconds that it takes for a kettle to boil, $n$, is inversely proportional to its power in kilowatts, $p$.
The equation of proportionality is
\[
n=\frac{270}{p}
\]
Work out the power of the kettle if it takes 90 seconds to boil.
If your answer is a decimal, give it to 1 d.p.
Answer
\(\boxed{3.0}\) is the power of the kettle in kilowatts.
Step 1 ：Given that the number of seconds to boil, $n$, is inversely proportional to the power in kilowatts, $p$. The equation of proportionality is \[n=\frac{270}{p}\]
Step 2 ：We need to find the value of $p$ when $n = 90$ seconds. Substitute $n = 90$ into the equation:
Step 3 ：\[90=\frac{270}{p}\]
Step 4 ：To solve for $p$, multiply both sides by $p$ and then divide by 90:
Step 5 ：\[p=\frac{270}{90}\]
Step 6 ：\[p=3.0\]
Step 7 ：\(\boxed{3.0}\) is the power of the kettle in kilowatts.
