How to construct a linear equation of this question and solve it?

Question

A rower travels upstream at 6 km/h and back to the starting place at 10 km/h. The total journey takes 48 minutes. How far upstream did the rower go?

Answer 1

upstream at 6 kph, back at 10 kph, total time = 48 minutes = 48/60 hr = 4/5 hr = .8 hour

distance = rate of speed times time

d =rt

t = d/r = (d/2)/6 + (d/2)/10 = d/12 +d/20 = (5d +3d)/60 = 4/5

8d/60 =2d/15 = 4/5

2d/3 =4

2d =12

d = 12/2 = 6 up and back

3 km upstream, 3 km downstream

3 km at 6 km per hour = 1/2 hour

3 km at 10 km per hour = 3/10 hour

1/2 hr + 3/10 hr = 8/10 = 4/5 hr = 48 minutes up & back