Answer:
 t = 67.04 s
Step-by-step explanation:
given,
time taken by Lace on the side walk = 2 min 47 s
 = 167 s
time taken by the Lace while walking = 112 s.
now, time taken by the Lace when he is walking on the side walk = ?
Assume the distance be equal to 'd' 
speed of Lace on side walk
 we know, distance = speed x time
 

speed of the lace while walking
 

time taken by Lace to cover the distance by walking on the side walk
 

 

 

  t = 67.04 s
time taken by the Lace walking on the side walk is equal to 67.04 s