## Elementary Algebra

It takes 2$\frac{1}{4}$ seconds to download 1 song, which is equal to $\frac{9}{4}$ seconds. To download 16 songs, we multiply the time needed for 1 song by 16. So, $\frac{9}{4}$ $\times$ 16 = $\frac{9 \times 16}{4}$ Factor the numerator and the denominator: $\frac{9\ \times\ 4\ \times 4}{4}$ = Cancel the common factors in the numerator and the denominator to obtain: 9 $\times$ 4 = 36 seconds