Question

An unopened cereal box contains 15/28 cubic foot of cereal. If the box is full, and the length and height of the box are5/7 and 1 1/2 feet, respectively, what is the width of the box?

Answer 1

Volume is height times length times width

V = 15/28 ft^3
h = 11/2 ft
l = 5/7
w = ?

So the unsolved equation is:
V = h × l × w

Separate the w by diving both sides by h and l:
$w = \frac{v}{hl}$
Then plug in the numbers:
$w = \frac{( \frac{15}{28}) }{( \frac{11}{2} ) \times ( \frac{5}{7}) }$
Which, with the fractions flipped, equals:
$w = ( \frac{15}{28} ) \times ( \frac{2}{11} ) \times ( \frac{7}{5} ) \\ w = \frac{210}{1540}$
$w = \frac{3 \times 7 \times 10}{10 \times 2 \times 7 \times 11} \\ w = \frac{3}{2 \times 11} \\ w = \frac{3}{22}$
The width of the box is 3/22 ft