Question 62751
Given the speed of the first printer = 3pages perminute

And the speed of the second printer = 5 pages permintue

We shall use the formula for the speed,

Speed of the first printer =  number of pages printed / time taken  

=> 3 = number of pages printed / 20 + t 
   
   3 * (20 +t) = number of pages printed -->(1)

Speed of the second printer = number of pages printed / time taken

=> 5 = number of pages printed / t

   5 * t = number of pages printed -->(2)


Equating equation(1) and (2), we get

3(20 + t) = 5 * t

60 + 3t = 5t

60 = 5t - 3t

60 = 2t

60/2 = t

30 = t

Therefore it will take 30min for the second printer to catch up to the first printer.