A piece of cloth cost Rs 35. if the length of the piece would have been 4m longer and each meter cost Re 1 less , the cost would have remained unchanged. how long is the piece? Pick.
A) 5 mtrs B) 10 mtrs C) 12 mtrs D) 15 mtrs E) 18 mtrs

Rationale: if length of piece is x and cost per mtr is c , then x * c = 35 or c = 35 / x ( x + 4 ) * ( c - 1 ) = 35 or x * c + 4 c - x - 4 = 35 or 35 + 4 c - x - 4 = 35 4 c - x = 4 4 * ( 35 / x ) - x = 4 x = 10 mtrs answer : b
Answer: B