a runs twice as fast as b and gives b a start of 71 m . how long should the racecourse be so that a and b might reach in the same time ?
"ratio of speeds of a and b is 2 : 1 b is 71 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 71 m is 71 / 1 = 71 m so the total time taken by a and b to reach = 2 * 71 = 142 m answer : d"
multiply(71, const_2)