9 machines of model A and 5 machines of model B working in a day to print 905 bucks.
Solution:
Given that
Model A can print 70 bucks per day
Model B can print 55 bucks per day
Total number of printing presses = 14
Total number of bucks printed by machines of Model A and Model B in 1 day = 905
Let assume number of printing presses of model A = "y"
As total 14 printing presses are there and "y" are of model A, so remaining that is (14 – y) will be of model B.
Number of bucks printed by 1 machine of model A in one day = 70
So number of bucks printed by "y" machine of model A is given as:

Number of bucks printed by 1 machine of model B in one day = 55
So number of bucks printed by (14 –y) machine of model B is given as:

Also given that Total number of bucks printed by machines of Model A and Model B in 1 day = 905
Total number of bucks printed by machines of Model A and Model B in 1 day = number of bucks printed by "y" machine of model A + Number of bucks printed by (14 –y) machine of model B

Number of printing presses of model A = y = 9
Number of printing presses of model B =(14- y) = 14 – 9 = 5
Hence 9 machines of model A and 5 machines of model B working in a day to print 905 bucks.