Question

the ratio of the cost of the book and a notebook is 9:5. the cost of the notebook is ₹28 less than the cost of the book. find the total cost of the book and the notebook​

Answer 1

$\large\underline{\sf{Solution-}}$

Given that

• The ratio of the cost of the book and the cost of a notebook is 9:5

Let us assume that

• Cost of 1 book = ₹ 9x

and

• Cost if 1 notebook = ₹ 5x

According to statement,

☆ The cost of the notebook is ₹28 less than the cost of the book.

$\rm :\longmapsto\:5x = 9x - 28$

$\rm :\longmapsto\:5x - 9x = - 28$

$\rm :\longmapsto\: - 4x = - 28$

$\bf\implies \:x = 7$

Hence,

• Cost of 1 book = 9 × 7 = ₹ 63

• Cost of 1 notebook = 5 × 7 = ₹ 35

So,

• Total Cost of 1 book and 1 notebook = 63 + 35 = ₹ 98

Basic Concept Used :-

Writing System of Linear Equation from Word Problem.

1. Understand the problem.

• Understand all the words used in stating the problem.

• Understand what you are asked to find.

2. Translate the problem to an equation.

• Assign a variable (or variables) to represent the unknown.

• Clearly state what the variable represents.

3. Carry out the plan and solve the problem.