mathematics

Andy and Marcus each bought the same storybook and both of them started reading their books on the same day. Marcus read 3 fewer pages than Andy each day. Marcus took 80 days to finish his storybook while Andy took 30 days fewer than him. Find the number of pages in the storybook.

Let   N  be  the  number  of pages  that  Marcus  reads  each day  and N + 3  the number  that Andy reads each day

Note {  it takes Andy  50  days to finish....so we have

80N  =   50 (N + 3)

80N  =  50N  +  150

80N - 50N   =  150

30N  =  150

N =  150  / 30    =    5

Number  of pages in the story book =    80(5)  =   400