In a 500 m race, the ratio of the speeds of two contestants A and B is 3 : 4. A has a start of 170 m. Then, A wins by:	Choose the correct choice from the following
A) 60 m B) 20 m C) 43 m D) 20 m E) 23 m

Rationale: "to reach the winning post a will have to cover a distance of ( 500 - 170 ) m , i . e . , 330 m . while a covers 3 m , b covers 4 m . while a covers 330 m , b covers 4 x 330 / 3 m = 440 m . thus , when a reaches the winning post , b covers 440 m and therefore remains 60 m behind . a wins by 60 m . answer : a"
Answer: A