Correct option is (b) 40%
Let us take the C.P. = Rs. 100.
∴ S.P. at 19% gain = Rs.(100 + 19) = Rs. 119 ..........(i)
Let the M.P. = Rs. x.
Then, the S.P. at a discount of 15% = \(x - x\times \frac {15}{100} = \frac{17x}{20}\) .........(ii)
Comparing (i) & (ii),
\(\frac{17x}{20} = 119\)
⇒ \(x = \frac{20}{17} \times 119\)
⇒ x = Rs.140.
So, the M.P. = Rs.140 and the C.P. = 100.
The increment in price in order to get 19% profit = Rs.(140 − 100)
= Rs. 40
= 40%.
(Since the C.P. = Rs. 100)