The mark-up for a 75 dollar golf club is 80 dollars. Find the percent of the mark-up.

So from 75 to 80 and 75 is 100%

80-75=5

5 is x% of 75

x%=percent markup

5=x% times 75

% means parts out of 100 so

x%=x/100

5=x/100 times 75

5=75x/100

75x/100=75/100 times x

75/100=3/4

5=3/4x

multiply both sides by 4/3

20/3=x

6.6666%

the percent mark up is 6.6666%