Sam has 3 more than twice the number of baseball cards that Catherine has. Together Sam and Catherine have 51 baseball cards. How many cards do Sam and Catherine each have?

2x+3y=12 x-y=6 solve the following system equations

The sat and act tests use very different grading scales. the sat math scores follow a normal distribution with mean 518 and standard deviation of 118. the act math scores follow a normal distribution with mean 20.7 and standard deviation of 5. suppose regan scores a 754 on the math portion of the sat. how much would her sister veronica need to score on the math portion of the act to meet or beat regan's score?

2.5 milligrams is equivalent to how many grams