Question

Shalini buys 2 pens and 4 pencils from a stationery shop. If the cost of one pencil and one pen is ₹2.5 and ₹7.5 respectively, how much money does she need to pay?

• A. ₹15
• B. ₹20
• C. ₹30
• D. ₹25

Answer 1

The correct option is D ₹25

The cost of one pencil = ₹2.5
The cost of four pencils = ₹2.5 × 4
$\begin{array}{ccc}\frac{25}{10}\times 4& =& \frac{5}{2}\times 4\\ & =& 5\times 2\\ & =& 10\end{array}$
The cost of four pencils is ₹10.

The cost of one pen = ₹7.5
The cost of two pens = ₹7.5 × 2
$\begin{array}{ccc}\frac{25}{10}\times 4& =& \frac{5}{2}\times 4\\ & =& 5\times 2\\ & =& 10\end{array}$The cost of two pens is ₹15.
Total cost = ₹10 + ₹15 = ₹25