1. **State the problem:** A student has 72 music files divided into four folders: techno, hip hop, reggae, and classic rock. The fractions of songs in techno, hip hop, and reggae are given, and the rest are classic rock. We need to find how many songs are in each folder. 2. **Identify the fractions:** - Techno: $\frac{1}{3}$ of the songs - Hip hop: $\frac{1}{4}$ of the songs - Reggae: $\frac{1}{6}$ of the songs - Classic rock: the rest 3. **Calculate the number of songs in each folder:** - Total songs: 72 - Techno songs: $72 \times \frac{1}{3} = 24$ - Hip hop songs: $72 \times \frac{1}{4} = 18$ - Reggae songs: $72 \times \frac{1}{6} = 12$ 4. **Calculate the number of classic rock songs:** - Sum of known songs: $24 + 18 + 12 = 54$ - Classic rock songs: $72 - 54 = 18$ 5. **Summary:** - Techno: 24 songs - Hip hop: 18 songs - Reggae: 12 songs - Classic rock: 18 songs This completes the distribution of the 72 songs into the four folders.