What is 509mL when its converted to km?

Suppose that sahil knows that 45 people with ages of 18 to 29 voted. without using a calculator, he quickly says then 135 people with ages of 30to 49 voted. is he correct? how might sohil have come up with his answer so quickly?

Point a (7,3) is translated to a'(16,-9). which rule describes the translation?

What is the approximate mark up percentage rate before m equals $1740 marked up from p equals $19,422