CAT 2014 | Question: 8

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. 

ONWARD, $10$; ONWARD, $10$. Which of the following statements about the above instructions is true? 

1. $n2 - n1=20$ only if $n1=0$ 
2. $n2 - n1=20$ if $M>20$ and $n1=1$ 
3. $n2 - n1=10$ if $M=21$ and $n1=0$ 
4. $n2 > n1$ if $M > 0$ 

Answer 1

ONWARD, 10 ; ONWARD, 10 would effectively mean a ONWARD 20 i.e. n2-n1 = 20, (if M – n1
≥ 20) .or n2 = M (if M – n1 < 20). if M>20 and n1=1,then M – n1 > 20, and hence n2-n1 = 20.

Ans is (B)