A = bh
Plug in what we know:
18 1/3 = 3 1/3b
Divide 3 1/3 to both sides:
(18 1/3) / (3 1/3) = b
Convert both of them into improper fractions:
55/3 / 10/3 = b
Flip the 2nd fraction and multiply:
55/3 * 3/10 = b
Multiply the numerators and denominators together:
165/30 = b
Convert to a mixed number:
b = 5 1/2