By selling 14 watches of equal cost price at the rate of Rs. 450 each, there is profit equal to the cost price of 4 watches. The cost price of the watch is = ?

Answer: Option A

Let the cost price of the watch is = Rs. x
According to the question,
⇒ Profit = Selling price - Cost price
⇒ 4x = 14 × 450 - 14x
⇒ 18x = 14 × 450
$$\Rightarrow x=\frac{14\times 450}{18}=350$$
Cost Price of a watch = Rs. 350