1. If 6, x, 10, 15 are in proportion what is the value of x?

2. If p, 9, 8, 6 are in proportion what is the value of p?

3. If 25, 35, 35, m are in proportion what is the value of m?

4. At 2 rupees commission per sale of book, what is the commission for sale of 40 books?

5. At 3 rupees commission per sale of book, what is the commission for sale of 36 books?

6. At 4 rupees commission per sale of book, what is the commission for sale of 25 books?