First solution:

Since all machines are identical, each of them produces the same amount of work. Together they produce 270 bottles per minute so one machine produces of 270 bottles or = 45 bottles per minute. In 4 minutes every machine produces 4 times more or 45*4 = 180 bottles. 10 machines produce 10 times more than 1 machine. Thus 10 machines in 4 minutes can produce 180*10 = 1,800 bottles

Second solution:

10 machines is 1.5 times more (or greater) than 6 machines. In 4 minutes machines can produce 4 times more bottles than in 1 minute. So 10 machines in 4 minutes can produce
270*1.5*4 = 270*6 250*6 = 1,500 bottles (or greater). So, B is the best choice.

Strategy

Modeling the problem helps to understand it clearly. Sometimes approximate calculation is the only way to solve the problem. But try to check the answer whenever possible.

Pitfalls:

Do not miss the fact that 6 machines work together instead of 1 (answer E is wrong) and time matters (answers C and D are wrong).

Useful formulas:

If x machines produces p items then the productivity of 1 machine is items or of the total work.