Question

Josiah kept track of how many songs of each genre were played in an hour from his MP3 player. The counts are displayed in the table below. He has a total of 1,500 songs on his player. Josiah predicted the number of rock songs on his MP3 player to be 300 songs. Which statements about his solution are true? Select three choices. Josiah’s Music Sample 1 Sample 2 R & B 5 R & B 4 Pop 4 Pop 3 Classical 3 Classical 5 Jazz 2 Jazz 4 Rock 6 Rock 4 Josiah’s work: StartFraction 10 over 20 EndFraction = StartFraction x over 1,500 EndFraction. StartFraction 10 times 30 over 20 times 30 EndFraction = StartFraction x over 1,500 EndFraction. 300 = x. He should have found the average of the number of rock songs by averaging 4 and 6 to get 5. He did not multiply the numerator and denominator by the correct number to equal 1,500. His answer will be one-half of what he got because he did not divide 10 by 2 when setting up the proportion. He can only solve the proportion by multiplying the numerator and denominator by a common multiple. He should have multiplied the numerator and denominator by 75, not 30, because 20 times 75 = 1,500.

Answer 1

The following statements about Josiah's solution are true:

1. He predicted the number of rock songs on his MP3 player to be 300 songs. (This is stated in the problem description.)

2. His answer will be one-half of what he got because he did not divide 10 by 2 when setting up the proportion. (This is true, as he should have divided both the numerator and denominator of the first fraction by 2 to simplify it.)

3. He should have multiplied the numerator and denominator by 75, not 30, because 20 times 75 = 1,500. (This is true, as he needed to find a common multiple of 20 and 1,500 to set up the proportion correctly.)