10th Class Mathematics Pair of Linear Equations in Two Variables Question Bank Case Based (MCQs) - Pair of Linear Equations in Two Variables

The cost of one ring game and one balloon game is:

A) Rs.2and Rs.4

B) Rs.4 and Rs.2

C) Rs.8 and Rs.2

D) Rs.6 and Rs.3

Correct Answer: A

Solution :

Solving the equations \[4x-3y=-4\] and \[4x+3y=20\] by the method of elimination by substitution:

From eq. (1): \[4x=3y-4\] ...(3)

Substituting in eq. (2),

\[(3y-4)+3y=20\,\,\,\,\,\,\,\,\Rightarrow \,\,\,\,\,\,6y-4=20\]

\[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,6y=24\,\,\,\,\,\,\,\,\,\,\Rightarrow \,\,\,\,\,\,\,\,\,\,y=4\]

Substituting \[y=4\] in eq. (3),

\[4x=3\times 4-4=8\] or \[x=2\]

Therefore, cost of one ring game \[=Rs.2\] and cost of one balloon game \[=Rs.4\].

So, option [a] is correct.