Problem Solving

Hi All,


I have few question papers which I downloaded. I am not able to find answer for few of them. It would be really great if you guys could help me out. Below are the questions.

1. At the end of each year the value of a certain antique watch is c percent more than its value one year earlier,where c has the same value each year.If the value of the watch was k dollars on January1,1992 and m dollars on January1,1994,then in terms of m&k,what was the value of the watch, in dollars,on January 1,1995

2.The function f is defined by f(x)=-1/x for all nonzero numbers x. If f(a)=-1/2 & f(ab)=1/6, then b= ?

I am getting answer -1/3 but the bank says -3. Which one is the correct answer.

3.The toll for crossing a certain bridge is $.75 each crossing.Drivers who frequently use the bridge may instead purchase a sticker each month for $13 & then pay only $.3 each crossing during that month. If a particular driver will cross the bridge twice on each of x days next month & will not cross the bridge on any ther day, what is the least value of x for which this driver can save money by using the sticker?

Choice of answer - 14,15,16,28,29

4.How many different 6-letter sequences are there that consist of 1A,2B's,3C's?

Choice of answer - 6,60,120,360,720.

I am getting 720 but the bank says 60.Which one is the correct answer.


5. If n is a positive integer, what is teh remainder when (7to the power 4n+3)(6to the powern) is divided by 10?

Choice of answer - 1,2,4,6,8.

Working simultaneously & independently at an identical constant rate, 4 machines of a certain type can produce a total of x units of product P in 6 days. How many of these machines, working simultaneously & independently at this constant rate, can produce a total of 3x units of product P in 4 days?

Choice of answer - 24,18,16,12,8.


I have a dozen question papers with me. Answers are also provided. I am uploading them, hope it will be helpful.

Cheers

Rakesh