13. A payment of $6500 is due in five months and another payment of $9500 is due in ten months. Calculate the value of a single payment to be made in seven months that is equivalent to these two payments if money earns 6.5% p.a. simple interest. Use seven months from now as the focal date.

15. Sam was supposed to pay $700 seven months ago and is supposed to pay $800 in 11 months. He did not make the first payment as scheduled and will not make the scheduled payment in 11 months. Instead, he would clear the loan 19 months from now. What would the value of this single payment in 19 months be if the interest rate on the loan is 7% pa? Use 19 months from now as the focal date.

17. You donated $5000 to charities A, B and C in the ratio of 12:5:3. How much money did you donate to each charity?