Rohit, Harsha and Sanjeev are three typists who, working simultaneously, can type 216 pages in four hours. In one hour, Sanjeev can type as many pages more than Harshs as Harsha can type more than Rohit. During a period of five hours, Sanjeev can type as many pages as Rohit can during seven hours How many pages does each of them type pei hour?

Let number of pages types per hour by Rohit, Harsha and Sanjeev respectively be $$x,y,z$$

=> $$4(x+y+z)=216$$

=> $$x+y+z=54$$ -----------(i)

Also, $$z-y=y-x$$

=> $$x+z-2y=0$$----------(ii)

Subtracting equation (ii) from (i), we get : $$y=18$$

=> $$x+z=36$$ --------------(iii)

Also, $$5z=7x$$ ------------(iv)

Now, solving equations (iii) and (iv), we get : $$x=15$$ and $$z=21$$

$$\therefore$$ Pages typed per hour by Rohit, Harsha and Sanjeev respectively are : 15,18,21

=> Ans - (D)