 
 <translate> A shop is offering a discount on pens. If you buy 10 pens at the regular price, you can get the next 10 for half off. A customer came in and bought 20 pens for $30. What's the regular price of one pen in dollars? Let's think first. Chain of thought: <ibo> Otu ụlọ ahịa na-emefu ego n'ụrọ. Ọ bụrụ na ị zụta mkpịsị 10 n'ọnụ ego nkịtị, ị pụrụ inweta mkpịsị 10 na-esote n'ọnụ ego ọkara. Otu onye ahịa batara ma zụta mkpịsị akwụkwọ 20 n'ọnụ ego $30. Ego ole ka a na-akwụkarị maka otu mkpịsị akwụkwọ na dollar? Ka anyị buru ụzọ chee echiche. Ụzọ iche echiche: 