4. A owes B, Rs. 1120 payable 2 years hence and B owes A, Rs. 1081.50 payable 6 months hence. If they decide to settle their accounts forth with by payment of ready money and the rate of interest be 6% per annum, then who should pay and how much:

5. If Rs. 10 be allowed as true discount on a bill of Rs. 110 due at the end of a certain time, then the discount allowed on the same sum due at the end of double the time is:

6. A man purchased a cow for Rs. 300 and sold it the same day for Rs. 360, allowing the buyer a credit of 9 years. If the rate of interest be 7 % per annum, then the man has a gain of: