Trucks are delivering gravel to a construction site each truck hold 7.5 cubic yards of gravel. the weight of 1 cubic yard of gravel is 1.48 tons. the gravel will be placed in containers that each hold 3.7 tons of gravel. how many contaoners of this size are needed to hold all the gravel from one truck

The first thing you must do is to calculate the weight of the gravel (w) that the truck holds (7.5 yards³). So, you have:

 If the weight of 1 yard³ is 1.48 tons, then the weight of 7.5 yards³ is:

 w=7.5x1.48 tons
 w=11.1 tons

 The problem says that the gravel will be placed in containers that each hold 3.7 tons of gravel,so, If they need 1 cotainer to place 3.7 tons, how many containers they need to place 11.1 tons?

 1 container3.7 tons of gravel
                 x11.1 tons of gravel

 x=(11.1x1)/3.7
 x=11.1/3.7
 x=3 containers

 How many containers of this size are needed to hold all the gravel from one truck?

 The answer is: 3 containers. 

3x+9+4x+x=8x+9that's the answer for your question.