Mathematics, wisdom and wisdom, climbing the peak, my first topic.
I'm also studying this problem. In fact, it's not the least money, but the cheapest solution you use.
No.: 1
18( 1+3+5)= 2 (vehicle)
2× 1=2 (vehicle)
2×5= 10 (vehicle)
150× 2+100× 6+80×10 =1700 (yuan)
I'll give you a supplementary answer in the second sentence.