Your Neighbor Goes to the Post Office Once a Month

Your neighbor goes to the post office once a month and picks up two checks,one for $18,000 and one for $4,000.The larger check takes 4 days to clear after it is deposited; the smaller one takes 6 days.Assume 30 days per month.What is the weighted average delay?

A) 4.21 days
B) 4.36 days
C) 4.78 days
D) 5.00 days
E) 6.00 days