Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Problem: a is twice as good a work man as b and together they finish the work in 4 days. in how many days a alone can finish the work ?
Options: a. 3, b. 2, c. 7, d. 9, e. 6
e

Problem: 6 men and 8 women can complete a work in 10 days. 26 men and 48 women can finish the same work in 2 days. 15 men and 20 women can do the same work in - days.
Options: a. 4 days, b. 6 days, c. 2 days, d. 8 days, e. 10 days
a

Problem: 0.0008 ? = 0.02
Options: a. 40, b. 4, c. 0.4, d. none of these, e. 0.04

e