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
30 pens and 75 pencils were purchased for 690. If the average price of a pencil was 2.00, find the average price of a pen.

a) 10
b) 11
c) 18
d) 13
e) 14