[Heinemann FP3 Chapter 5A Question 17]
Air you made a mistake in posting the question.
It should be
Okay i did the question once, got the correct answer but made a mistake in my working.
Initially i made the mistake of doing
then subsituting the values into the equation. solved the quad and got 2.222.
did you notice the error though ?
Here is my solution, not guarantee that is is correct.
then sub the values
which disagrees with everybody.