Problem

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.

Solution

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.

From Solvely APP
Source: https://solvelyapp.com/problems/35362/

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