Now the way I've read that is that he is on the sand, and he needs to drive 32km on the sand to get to the straight paved road which is 16km to the power plant...but seeing as how dodgy the 2nd sentence is there, I'll do it in reverse as well.
So the first way;
1. 32km @ 48km/h
2. 16km @ 80km/h
1. t=32/48 hours
t=2/3 hr = 40min (by doing 2/3 times 60)
2. similarly t=16/80 = 12 min
so the total time is 52mins, he starts at noon, he's 2 mins late.
And the second way;
1. 32km @ 80km/h
2. 16km @ 48km/h
1. t=32/80 hrs = 24min
2. t=16/48 hrs = 20min
total time is 44mins so he's got 8minutes left.
...Now it just depends if you're an optimist, a pessimist or if you can interpret that 2nd sentence better.
My reasoning for picking the first way was that; it says he's 32km from said road, and that said road is 16km, so the 32km must be the sand??