Answer

With this kind of a question, never try to brute force it - that's not what they are testing. They want to see if you can find a faster / easier way to evaluate it. In this case, you know that multiplying two-digit numbers with 11 is easy - take the first digit (5), sum the two digits (5+4), take the third digit (4): $54 \cdot 11 = 594$. Now we're left with a multiple of 10 and a division of 100 since 54 is a percentage. We simply divide our result with 10, arriving at $59.4$