A shopkeeper sells an article for ₹ 21,384 including 10% tax. However, the actual rate of Tax is 8%. Find the extra profit made by the dealer.

S.P. of the article = ₹ 21,384

Tax = 10% on the M.P.

Let the M.P. be ₹$x$.

Tax = 10% on ₹ $x$

$\Rightarrow \dfrac{10}{100} \times x\\[1em] \Rightarrow \dfrac{1}{10} \times x\\[1em] \Rightarrow \dfrac{x}{10}$

S.P. of the article = M.P. + Tax on M.P.

$\Rightarrow x + \dfrac{x}{10} = 21,384\\[1em] \Rightarrow \dfrac{10x}{10} + \dfrac{x}{10} = 21,384\\[1em] \Rightarrow \dfrac{(10x + x)}{10} = 21,384\\[1em] \Rightarrow \dfrac{11x}{10} = 21,384\\[1em] \Rightarrow x = \dfrac{21,384 \times 10}{11}\\[1em] \Rightarrow x = \dfrac{2,13,840}{11}\\[1em] \Rightarrow x = 19,440$

M.P. = ₹ 19,440

Actual tax = 8% of the M.P.

$\Rightarrow \dfrac{8}{100} \times 19,440\\[1em] \Rightarrow \dfrac{1,55,520}{100}\\[1em] \Rightarrow 1,555.20$

Actual S.P. of the article = M.P. + Tax on M.P.

= ₹ 19,440 + ₹ 1,555.20

= ₹ 20,995.20

Profit made by the dealer = S.P. charged by dealer - Actual S.P.

= ₹ (21,384 - 20,995.20)

= ₹388.80

Hence, the deal made the profit of ₹388.80