At a golf ball factory, 60 golf balls were inspected and 48 of them passed inspection. out of 2,500 golf balls made at the factory about how many would you predict would fail on inspection

Given that among the 60 golf balls, only 48 of them passed the inspection. This means, the other 12 golf balls did not passed.

To get the percentage of these data, we will use the formula:

is/of = %/100

Where,
is = 12 (number of golf balls that failed the inspection)
of = 60 (total number of golf balls)
% = x 

Therefore,

is/of = %/100
12/60 = %/100
0.2 = %/100
100 (0.2) = %
20 = %

The percentage of the golf balls that did not passed the inspection is 20%.

If there are 2,500 golf balls to be inspected, let us assume that 20% of them will not pass.  Again, using the percentage formula:

is/of = %/100

where,
is = x
of = 2,500
% = 20

Let us determine the number of golf balls that will fail the inspection.

is/of = %/100
x/2,500 = 20/100

Let us cross multiply (multiplying the numerator of one fraction by the denominator of the other fraction).  

100x = 2,500 (20)
100x = 50,000
x = 500

There are 500 golf balls that are expected to fail on inspection.

The pie is multyplued by the second step