Which is the equation for the nth term of the geometric sequence: -4,8,-16...?

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Can someone me out here number 4 plz

How many grams the dog will eat in 3 days?