The ratio of pen, pencil and eraser to a box is 3 ∶ 2 ∶ 1. If the prices of each pen, pencil and eraser are 3 rupees, 2 rupees and 2 rupees respectively and the amount spent on the box is 750 rupees, then find out the number of pen in the box.
1
151
2
152
3
153
4
150