Question

I need help with my cousins homework

Answer 1

Number 7:

Downloading 3 songs a day means that you have $3n$ after $n$ days.

So, on day 15 you will have

$3\cdot 15 = 45$ songs

You will have more than 40 songs when

$3n>40\iff n>\dfrac{40}{3} = 13.\overline{3}$ days

So, the first integer bigger than our value is 14.

Number 8:

To compute the volume of prisms like these (all sides are perpendicular), you simply have to multiply the dimensions:

$V = 5\dfrac{3}{5}\cdot 2\dfrac{1}{8} \cdot 4\dfrac{2}{3} = \dfrac{1937}{120} \approx 16.14$ cubic feet

Assuming that the sides are written with mixed fraction.