Question 1179148
the distance between London and New York is 320 Km. A train takes x hours to travel between London and New York.
(a) Write down an expression in terms of x, for the average speed of the train [1]

Average speed of train = {{{320/x)}}} km/h

(b) A car takes 2 ½ hours longer than a train to travel between London and New York. 
Let average speed of car be x Km/h
speed of train =x+80 Km/h

320/x - 320/(x+80) =5/2  
(320(x+80) -320x)/(x(x+80))=5/2 
 
320(x+80) -320x = x(x+80)*(5/2)

320x +25600 -320x =(x^2+80x)*(5/2)

25600=(x^2+80x) *(5/2)

51200=5x^2+400x

5x^2+400x -256000=0

x^2+ 80x -51200=0