Quarters (US $ 0.25) are stacked in 18 columns. The first column has 10 quarters and each subsequent column has 3 quarters more than the previous column. Find the total number of quarters.	Choose the correct choice
A) 648 B) 630 C) 578 D) 639 E) 646
Number of coins in the 18 columns forms an AP with first number 10 and last 61   Avg is 35.5 and the total number of coins is 35.5*18   Answer is 639
<result>D</result>
Quarters (US $ 0.25) are stacked in 18 columns. The first column has 10 quarters and each subsequent column has 3 quarters more than the previous column. Find the total number of quarters.