Let m be the no of trucks and n be the no of passenger vehicles...
Then m + n = 600
and 100m + 45n = 29200
Multiplying 1st equation by 45, we have 45m+45n=27000
then subtracting from 2nd eqn we have, 55m = 2200 that is m=40.Then n=560
So we have 40 trucks and 560 passenger vehicle