Math一問~~~~~

From 2400 electonic components , x of them are chosen at random , of which 3 of them are defective .
a ) If the relative frequency of defective electronic components out of the chosen ones is 1/75 , find x .
b ) Among the 2400 pieces of electronic components , estimate the number of defective ones based on the above situation .
(a)
3/x=1/75
x=3*75
x=225
(b)
the number of defective ones
=2400*(1/75)
=32