 <translate> Since average price of a pencil = 2
∴ Price of 75 pencils = 150
∴ Price of 30 pens = (690 – 150) = 540
∴ Average price of a pen = 540⁄60 = 18
Thus, the answer is (C). <yor> Níwọ̀n ìgbà tí iye owó apapọ̀ tó wà fún péńsù kan jẹ́ 2 <unk> Iye tí wọ́n ń san fún pẹ́ńsù márùndínlọ́gọ́rin = àádọ́jọ <unk> Iye owó ọ̀pá 30 = (690 <unk> 150) = 540 <unk> Iye tí wọ́n máa ń ta búlọ́ọ̀mù kan = 540⁄60 = 18 Nítorí náà, ìdáhùn náà ni (C). 