Question

The total rainfall in Forks, Washington, this October was 8 3/8 in. In September, 60% less rain fell than in October.

How much rain fell in September in Forks, Washington?

Express your answer as a mixed number in simplest form.

Answer 1

If you would like to know how much rain fell in September, you can calculate this using the following steps:

60% of 8 3/8 in. = 60% * 8 3/8 = 60/100 * 67/8 = 201/40 = 5 1/40 in.

8 3/8 - 5 1/40 = 67/8 - 201/40 = 67/20 = 3 7/20 in.

The correct result would be 3 7/20 in.

Answer 2

Given:
October: 8 3/8 inches
September : 60% less rain fell than in October.

This means that only 40% rain fell in September based on the amount of rain that fell in October.

8 3/8 ⇒ (8*8)+3/8 = 67/8
40% is 4/10

67/8 * 4/10 = 268/80 = 3 28/80 or 3 7/20 or 3.35

28 ÷ 2 = 14
80 ÷ 2 = 40
14 ÷ 2 = 7
40 ÷ 2 = 20

In September 3 7/20 inches or 3.35 inches of rain fell.