Well if the book in that link is current, it still has the wrong explanation of Ohm's Law with a led, that was mentioned in the thread I linked above.
From the linked book, page 30:
In the circuit shown in Fig. 5, you’re supplying 5 volts. The resistor offers 220 ohms
resistance. To find the amperage used by the LED, replace the values in the equation.
You should have 5=I*220
From the thread I linked (note the date):
The most obvious one is on page 30, where Ohms law is misused. They totally neglect the voltage-drop over the LED, which at this voltage levels is a big error. The calculations are thus wrong, and the conclusions in error.
And Mood Cue in that linked book does power the servo off the Arduino.
So that book in the link (which may or may not be the version shipping with the kit) is dodgy (being polite), so if it's the one the test is based on, so too is the test.