Acomputer program changed one number into another. the program changes 12 into 9, 20 into 15, and 100 into 75. what number will 60 be changed into?

45, Because all of the ratios between the numbers are 4/3
your left with the equation 60/x=4/3, now simply solve for x.
60/x=4/3 multiply by x
60=4x/3 multiply by 3
180=4x divide by 4
x=45