Norman and Suzanne Scarpulla own 30 shares of McDonalds Corp

Norman and Suzanne Scarpulla own 30 shares of McDonald\'s Corp. stock and 68 shares of Ford Motor Co.stock. As the New York Stock Exchange opened on a day in 2013, their stock portfolio consisting of these two stocks was worth $4107. The McDonald\'s stock was $80.55 more per share than the Ford stock. What was the price of each stock on that day?

Solution

Let price of each stock of McDonald\'s be x and of Ford Motor be y, then

30x+68y= 4107 (1)

x=y+80.55 (2)

Putting value of x from (2) in (1)

30(y+80.55) + 68y = 4107 => 30y+241.5+68y=4107 => 98y=4107-241.5 => y=3865.5/98 => y=39.44

x=39.44+80.55 => x=119.99