The weight of baggage deliver in 1 min by 1st belt = 3/5 tonne
The weight of baggage deliver in 1 min by 2nd belt = 1/2 tonne
The weight of baggage deliver in 1 min by both belt = 3/5 + 1/2 = 11/10 tonne
So, the two belts delivers 1 tonne in 10/11 min.
Hence, required time to deliver 33 tonne = (10/11) x 33 = 30 min