SOLUTION
Let's solve the question and see where Olga made a mistake
The question is
[tex]\frac{1}{4}(\frac{1}{3}k+9)=6[/tex]
Solving this we have
[tex]\begin{gathered} \frac{1}{4}(\frac{1}{3}k+9)=6 \\ \\ multiplying\text{ both sides by 4} \\ \\ \frac{1}{4}(\frac{1}{3}k+9)\times\frac{4}{1}=6\times4 \\ \\ (\frac{1}{3}k+9)=24 \end{gathered}[/tex]
Next step we move 9 to meet 24, we have
[tex]\begin{gathered} (\frac{1}{3}k+9)=24 \\ \\ \frac{1}{3}k=24-9 \\ \\ \frac{1}{3}k=15 \end{gathered}[/tex]
Now multiply 3 to both sides
[tex]\begin{gathered} \frac{1}{3}k\times3=15\times3 \\ \\ k=45 \end{gathered}[/tex]
Therefore k = 45 and not 5. So Olga made a mistake in the last step, which is step 3. So the answer is step 3
