Hey guys please help me solve these four questions.

Question 1:

On 2 May 2000, a man borrowed a sum of money from a bank at 6.5% p.a. simple interest and on 2 September 2000, the interest amounted to $137.50. Calculate the amount of money he borrowed.

Question 2:

A fish merchant bought a container of fish for $36,000. He sold 1/2 of the fish at a profit of 20% and 1/6 of it at a loss of 10%. At what price must he sell the remaining fish in order to make a profit of 15% on the whole?

Question 3:

(a) A garrision has enough food to last for 24 days. How much longer will the food last if each individual ration can be reduced by 20%?

(b) By how much will each individual ration have to be reduced if hte food is to last 40 days?

Question 4:

A scouts' camp has enough food for 36 days. How long will the food last if each scout's ration is reduced in the ration 4:5?

Thanks!