No real solution
you must take the square root of a -3 which gives you an imaginary number
The correct answer is: $20
Explanation:
3 pounds of hamburger is $6.
1 pound of hamburger is 
Now,
10 pounds of hamburger is 
Hence the correct answer is $20.
As its one significant figure you are looking at the first number and the second number. If the second number is greater than 5 then you round the first number up and vice versa. In this case there is an eight, which is bigger than 5 obviously so you round the first number to get 40000.
Well .5 of a million dollars is 500,000. so you are right the decimal of 500,000 is .5 million.
I think it is point 3. Hope that helps