CAT 2014 | Question: 7

Question

Answer the questions based on following data.

The pages of a book are numbered $0, 1, 2 …$ upto $M, M >0$. There are four categories of instructions that direct a person in positioning the book at a page. The instruction types and their meanings are :

1. NEW : Position the book at page No. $1$ 
2. END : Position the book at page No. $0$ 
3. ONWARD, $n$ :From the current page move forward by $n$ pages; if, in this process, page number $M$ is reached, stop at $M$. 
4. REGRESS, $n$ : From the current page, move backward by $n$ pages; if in this process, page number $0$ is reached, stop at page number $0$.

In each of the following questions, you will find a sequence of instructions formed from the above categories. In each case, let $n1$ be the page number before the instructions are executed and $n2$ be the page number at which the book is positioned after the instructions are executed. 

REGRESS, $5$; ONWARD, $5$. Which of the following statements is true about the above set of instructions? 

1. $n1=n2$ provided $n1 ≥ 5$
2. $n1=n2$ provided $n1>0$ 
3. $n2=5$ provided $M>0$ 
4. $n1>n2$ provided $M>0$ 

Answer 1

ONWARD 25, REGRESS 10 would effectively mean a ONWARD 15 i.e. n2-n1 = 15, (if M –
n1> 25) and n2 = M – 10 (if M – n1 < 25).  So if M = 10 and n1 = 0., then M – n1 < 25 and so n2 = 10 – 10 = 0. Hence, n1=n2.

so, Ans is (A)