A man sold 18 toys for Rs. 18900, gaining thereby the cost price of 3 toy find the cost price of a toy Choose the correct choice from the following answers.
A) s . 600 B) s . 800 C) s . 500 D) s . 900 E) s . 990

Rationale: "let the cost of one toy = x . then , cost of 18 toys = 18 x . gain = 3 x . sp of 18 toys = rs . 18900 . gain = sp â € “ cp 3 x = 18900 â € “ 18 x 21 x = 18900 x = rs . 900 . answer : option d"
Answer: D