The task is to generate the correct answer for a given math problem.

Problem: convert 2 / 5 to a decimal
0.4

Problem: an aeroplane covers a certain distance of 670 kmph in 6 hours . to cover the same distance in 6 1 / 4 hours , it must travel at a speed of
643

Problem: a bakery has 6 employees . it pays annual salaries of $ 19,000 to each of 2 employees , $ 21,000 to 1 employee , and $ 22,000 to each of the remaining 3 employees . which number is closest to the average ( arithmetic mean ) annual salary of these employees ?

$ 20,800