Question

A library charges ₹ 5 for issuing a book for one day and ₹ 1 per day thereafter. If Ritu had taken a book for 5 days, then find the total amount that is needed to be paid.

• A. 9
• B. 2
• C. 3
• D. 5

Answer 1

The correct option is A 9

Let total amount charged be y and number of days be x.

$\Rightarrow$ Total amount = (Amount charged for first day) + [(Amount charged for total number of days the book is kept -1) $\times$ (Amount charged from second day onwards)]
$\Rightarrow y=5+(x-1)\times 1$
$\Rightarrow y=5+(x-1)$
$\Rightarrow y=4+x$
$\Rightarrow y=4+5$
$\Rightarrow y=9$

This can also be interpreted using graph as shown below.
$\begin{array}{cccc}x& 0& 1& 2\\ y& 4& 5& 6\end{array}$

From graph of 5 days i.e. for x = 5, y = 9

$\therefore$ For 5 days, Ritu has to pay ₹ 9.