I am going to bye a three bags of plums and the cost of the plums are $4000 but I only have $300 how many more money do I need

well...

if all three bags cost $4,000 then you'll need $3,700.

but if one bag costs $4,000 then that'll equal to $12,000 which then you'll need $11,700.

i might've misundestood your question so please let me know if this is correct!

its 50 miles away from the starting point