DRDO Multi tasking staff Model paper 7

Tricks:
Time taken for walking one way = Time taken walking both ways/2 = (55/2) = 27.5 mins.
Time for riding one way= 37 - 27.5 = 9.5 mins.
Time taken to ride both way = 9.5 × 2 = 19 mins
Detailed solution:
Let the speed at walking and riding be ‘x’ and ‘y’ km/hours respectively and the distance be ‘d’ km in one direction
Total time = Time for walking + Time for riding
∴ 37/60 = d/x + d/y ----(1)
For walking both ways,
55/60 = d/x + d/x
∴ d/x = 55/120
Substituting in (1) we get,
55/120 + d/y = 37/60
∴ d/y = 19/120 ----(2)
For riding both ways,
Time = d/y + d/y = 2(d/y) = 2 × (19/120) = 19 min
∴ To ride both ways, the person will take 19 min