In a 400 m race,A covers the distance in 60 seconds and B in 100 second.In this race A beats B by :
Select.
A) 20 m  B) 125 m  C) 120 m  D) 160 m  E) none of these

Rationale: "solution distance covered by b in 40 sec . = ( 400 / 100 x 40 ) m = 160 m . ∴ a beats b by 160 metres . answer d"
Answer: D