Q3.    Form the pair of linear equations for the following problems and find their solution by substitution method.

                (iii) The coach of a cricket team buys 7 bats and 6 balls for Rs 3800. Later, she buys 3 bats and 5 balls for Rs 1750. Find the cost of each bat and each ball.

Answers (1)
P Pankaj Sanodiya

Let the cost of 1 bat is x and the cost of 1 ball is y.

Now, According to the question,

7x+6y=3800......(1)

3x+5y=1750......(2)

Now, From (1) we have 

y=\frac{3800-7x}{6}........(3)

Substituting this value of y in (2)

3x+5\left ( \frac{3800-7x}{6} \right )=1750

\Rightarrow 18x+19000-35x=1750\times6

\Rightarrow -17x=10500-19000

\Rightarrow -17x=-8500

\Rightarrow x=\frac{8500}{17}

\Rightarrow x=500

Now, Substituting this value of x in (3)

y=\frac{3800-7x}{6}=\frac{3800-7\times500}{6}=\frac{3800-3500}{6}=\frac{300}{6}=50

Hence, The cost of one bat is 500 Rs and the cost of one ball 50 Rs.

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