Question

The difference between the cost of a notebook and two times the cost of a pen is ₹40. If the cost of a pen is ₹15, then what is the cost of a notebook?​

Answer 1

☆ Elucidation :-

We have been provided with the following information :-

• The difference between two times the cost of a pen and a notebook is Rs. 40
• Cost of the pen is Rs 15

Let the cost of notebook be x and the cost of pen be y

According to the question,

=> x - 2y = Rs. 40

We have been provided the value of y as 15,therefore, we can simply put the value of y in the equation to derive the value of x, so,

$\sf : \implies \: x - 2y = 40 \: \: \: \: \: \: \: \: \\ \sf : \implies \: x - 2 \times 15 = 40 \\ \sf : \implies \: x = 40 + 30 \: \: \: \: \: \: \: \: \\ \sf : \implies \: x = 70 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Therefore, the cost of one notebook is $\boxed{ \bf \blue{\: 70 \: }}$.