Let P be the full price. Half of 50 is 25 so he paid 25P for them. A 40% discount leaves a price of 60%, or .60P for the other 25 so he paid (25)(.6P) for them. Add those and set the sum equal to 2260.

The perimeter of a rectangle is 2 times the length plus two times the length. If you call the length W, the length is 3W. What equation do you get from that?2) A rectangular courtyard is three times as long as it is wide. If the perimeter of the courtyard is 67 m, find the dimensions of the courtyard.

Let "B" be Belinda's score. Then Annie's score if (1+ 0.1)B= 1.1B (do you see why?). That means that the "combined score of the other two" is B+ 1.1B= 2.1B and Cassies score is 60% of that- .6(2.1B)=12.6B. Add those and set them equal to 504.3) Three girls are playing Scrabble. At the end of the game, the total of their scores adds up to 504. Annie scored 10% more than Belinda, while Cassie scored 60% of the combined scores of the other two. What did each player score?

Since you are asked for the mass of an oxygen atom, let "M" represent that mass. Then the mass of a a carbon atom is 3M. The mass of whole molecule is 2(3M)+ 6M= 6M+ 6M= 12M. Set that equal to 2.45 x 104) The mass of a molecule of a certain chemical compound is 2.45 x 10^{-22}g. If each molecule is made up of two carbon atoms and six oxygen atoms and the mass of one oxygen atom is (1/3) that of a carbon atom, find the mass of an oxygen atom.^{-22}and solve for M.

Any help would be much appreciated.