Question 671136
let distance to market be x m

Total time = 15 minutes= 900 seconds

Time going to market + time returnibg = total time
t=d/r

x/4+x/5 =900

Lcd = 20

Multiply equation by 20

5x+4x= 900*20
9x= 900*20
x= 900*20/9
x= 2000 meters