A tradesman gives 4% discount on the marked price and gives 1 article free for buying every 15 articles and thus gains 35%. The marked price is above the cost price by -

Answer: Option D

Let the C.P. of each article be Rs. 100
Then,
Cost Price of 16 articles
= Rs. (100 × 16)
= Rs. 1600
Selling Price of 15 articles
$$\begin{array}{rl}& \text{ = Rs}\text{.}\left(1600\times \frac{135}{100}\right)\\ & =\text{Rs}\text{. 2160}\\ & \text{S}\text{.P}\text{. of each article}\\ & \text{ = Rs}\text{.}\frac{2160}{15}\\ & =\text{Rs}\text{. 144}\end{array}$$
If S.P. is Rs. 96, marked price = Rs. 100
If S.P. is Rs. 144, marked price
$$\begin{array}{rl}& =\text{Rs}\text{.}\left(\frac{100}{96}\times 144\right)\\ & =\text{Rs}\text{. 150}\end{array}$$
∴ Marked price = 50% above C.P.