The ratio of pen, pencil and eraser in a box is 3 ∶ 2 ∶ 1. If the prices of each pen, pencil and eraser are Rs.. 3, 2 rupees and 2 rupees respectively and the amount spent on the box is Rs. 795, find out the number of pens in the box.
1
169
2
159
3
189
4
179