A runs twice as fast as B and gives B a start of 64m.How long should the racecourse be so that A and B might reach in the same time?	Choose the correct choice from the following choices:
A) 75 m .
B) 128 m .
C) 150 m .
D) 100 m .
E) none of the above

Rationale: "ratio of speeds of a and b is 2 : 1 b is 64 m away from a but we know that a covers 1 meter ( 2 - 1 ) more in every second than b the time taken for a to cover 64 m is 64 / 1 = 64 m so the total time taken by a and b to reach = 2 * 64 = 128 m answer : b"
Answer: B