First, let's determine the number of business cards left:
600
−
280
=
320 business cards left.
"Percent" or "%" means "out of 100" or "per 100", Therefore x% can be written as
x
/100
We can then write:
x
/100
=
320/
600
100
×
x/
100
=
100
×
320/600
100
×
x/
100
=
32000
/600
x
=
320
/6
x
=
53.33 rounded to the nearest hundredth.
53.33
% of business cards are left.
